Not sure what to do . how do I connect this War Thunder Forum account to my gaijin gaming accout?
sign into that account?
As above. You’ll want to ensure you use the correct manner to log in.
If you use the consoles, you login via Xbox live or Playstation. Or if you use steam, login with steam.
It’s automatically linked, if I’m not wrong you have to play 10 matches to be able to post something in the forums.