Some hints about NF2 about confusing stuff when coming from NF1

Captains

After login create one (up to 6) captains. Their names is the ingame name (which is bad that you have 6 different then).

Each captain starts complete new (nothing other than gold can be used from other captains)

It's for making different nations or different spezialized crews on same nation (see below)

Ship research

Research tree is similar to other games like WoT, WT.

Ship setups are more or less fixed. You can improve by research but using strange setups is no more possible.

You can research a complete nation with one captain. I won't advise cause you should use specialized crews for CV, BB+CA, DD+CL or SS shipclasses.

Battles

Islands

Bases which your team owns by >1% cappture already provide light to your team. Fast ships (DD,CL) can do an early cap.

You need to stop your ship within red circle for capping and right click that base to start dropping landing boats. Depending on shipclass your landing forces have different power for capping.

Bases that you own for more than 50% capture points provide additional features like radar, airbase (for bomber or recon  calls of the flagship), and respawn possibilities.

Jumping from base to another base (respawn with same ship) is possible by stopping at one base and selecting target base on map. Both bases needs to be >50% captured (=light blue color). Might cost DP (unsure).

Enemy bases can be shot and decapped for decreasing their health. After bringing them down you can cap them to make them your teams base.

Afterall killing enemys is what brings you the victory most times.

battle gui
Take a quick look at the short guides in harbour (left side menu) which gives a basic idea of what to do.

Ships are quite fast but shells are quite slow. You need to preaim a lot at long range shots.

CA/BB have primary and secondary gunssets. Use them both when enemy is in range from secondary guns. Thats why nobody uses manual aim causye you can't keep up aiming when using both gunsets which you should concerning fire power.

DD / CL have sonar as a "weapon". You need to select and "fire" it if you know/think a sub is near. Sonar needs a cool down time before it can be activated again. Low level DDs have mines instead of DCs.

Only higher level BB/CAs can use scouts (and all CVs of course). DD/CLs can't.

Try to get enemy in sight range of your bases and fight them from out of the dark. Pay attention not to do the other way round. Fast ships and scouts can help to scout such areas.

There is a radar option which shows enemys ships location on mini map even when unscouted. You need a radar base with more than 50% cap points. Haven't figured out by who and how it can be activated.

If you are the flagship of your team you can call a bomber raid and a recon option if you own an airfield base (>50%). Never was flag so don't know how to activate it. I guess from the map.

Look at the provided ingame AA guides for learing AAing with auto and manual aiming

EXP/rewards
You get crew EXP, ship EXP, free EXP and credits.

- ship EXP for research an the actual ship

- crew exp for leveling up and getting ability points (see below)

- free EXP for ship research on all ships

- credits. Your net income after auto repairs is quite low. Seems to be a limiting factor to make you buy prem (which doubles net income). With a "mastered ship" (= everything researched) credit earnings seem to be better.

Win or loss is most influence factor for EXP. Having a good game in a loss might give you the same EXP as having a bad game in a win.

Sailors
Probably the part with most differences to NF1. Because ability growth points and slot use becomes hard later I think it's a good idea to start different captains (and therefor crews) for making BBs / CV / Subs. One crew for all kind of ships (which is possible) might be a very bad crew unless you buy premium sailors.

Moral system

Your crew members have a moral factor which increases / decreases their ability.

Each loss decreases your crews moral while a win increases it. a At least you wins > loss so you don't need >50% winrate to keep the moral up.

sometimes you win a 3% moral boost after battle

I don't know minimum moral but max (non prem player) is 120%. You can get higher moral by buying prem items.

Leaving a battle before it's over is always a loss though you get EXP if you made damage! Don't do that too often!

captains levels

For each level up you you get one research point. Save up (don't spread!) and use the mentioned amount for getting an additional officer slot on your ships. Unused ponts are indicated by a brown "arrow up" next to your catains picture top right.

Officers

You have 4 different kind of officers for: waepons, support, special, pilots. You have a fixed amount of free slots for officers which you should buy and place right at the start!

If you don't wanna buy premium sailors (expensive) get those cheap 50 credit ones. Use the "battle station" button top right in harbour to view and place your officers.

There are 2 additional slots for each kind of sailor (4 slots for pilots). You need to unlock them by allocateing captains points.

a) weapons officers

You start with 1 on boat. Get the other 2 ASAP.

Making a BB crew you allocate your points (you get when leveling up) mainly to accuracy

for subs / DDs better go torpedo and just allocat a little to ACC.

b) support officers

you start with one and get put 3 (or 4?) additional ones. Get them ASAP.

The abilities are maintanance, repair and engi.

Maintanance seems to be the NF1 restorer but without the burning ability. Seems to affect the max level you could repair your ship to after a hit.

Repair is repair speed

Engi is overheat time (seems not to have speed effects).

Engis seems to be less needed than in NF1. I don't think you get minutes of overheat out of them.
And I haven't noticed a great need for the maintanance option in my DD so far.
For BB/CA/CV I would suggest to start with repair and maybe add engi / maintanance later.
DD/CL and maybe subs probably better go with engi + repair

c) special officers

capping: lets you cap faster.

sonar: increases range and fequency of use

anti sonar: decreases being detected when in a sub

If you drive DD/CLs you need sonar and anti-sonar when in a sub. All other ship classes go for the capping ability. Which is still useless, cause BBs shouldn't stop at islands to cap IMO. So no need for the captain to research this extra slots unless you really specialise your crew to DD, SS or APA.

d) pilots

You have anti aircraft, evasion and bomber ability. While anti.aircraft seems to be for fighter attack and bomber aibility also is clear I don't know when to use evasion ability. Also don't know how to use planes.
Only higher level BBs/CAs can use scouts.

Nations

Don't know much about nation advantages so far:
- KM seems not to have longest range and have weak shells. On paper KM BBs look weak. Don't know about speed, accuracy or reload though.
- US seems to hit quite hard but also might be balanced by slow reloads.
- IJN has lots of secondary guns and good damage. But other posts claim they are fragile.
- Don't know if UK is still the repair nation.

When I wrote something wrong please let me know so I can make a correction.