Play until you have at least 150,000 Credits and Points (minimum trade requirement if you
are under Level 30). Then, open a room in the trade area called "Please Donate Points".
High-level players will gladly give you some (by 'some', I mean 'a lot') of their Points
because Points become somewhat useless in higher levels. However, do NOT try to get
Credits (unless you get lucky and you are offered some).

Also:
http://trainworld.us/nf-guides/
http://www.trainworld.us/NF2/English/index.html

Just going to add in to Akin.

Yes, basically you want to do that to your sailors *proper classing* if you're going BB.
But if you want to use UK AA Gunners, you'll need to leave them as armament sailors up
until about 85 - 95 level to get some decent Reload stat from them.

Well, at least I think from the posts here in the UK section lol anyone correct me if I'm
wrong though..!

Class your sailors when they hit the necessary lvl. You will lose ability if you class
them too late. Or, am i wrong?

That makes sense, I'll just put em' on the useless spots on my Z99 and then level them.
Or is there a faster way?

Yes, like UmbralRaptor said. You can't use neutral sailors on a nation's ship.

That would be it. You need armament sailors of the appropriate level to access the
guns/torpedoes. Later on, you'll need them classed as gunners, heavy gunners, etc. to get
access to the higher level guns.