There are two types of activation method, Steam and Regular account.
1) For Regular Account who are NOT Steam account
Go to https://forum.navyfield.com/plugin.php?id=nf2_users:activateid&lang=en
2)For Steam users, you will need 2 steps to activate your account:
a) Go to https://forum.navyfield.com/member.php?mod=logging&action=login&referer=&lang=en to login to your Steam account by pressing the Steam login box
You will be redirected to Steam login page, login your Steam account
b)Then click Steam Step 2 or https://forum.navyfield.com/plugin.php?id=nf2_users:activateid&lang=en to enter the following info
Now you are ready for the sinking enemies!
NavyField: Fleet Mission Management Team