Trading is quite easy to do. or join up with a clan that show you the ropes in the game . it also depends on which server you decided to play. for example pve is more trading and npc hunting. while pvp is more player vs player combat.
Raiders tag a port. player clans then need to do hostility to take 100% then they are allowed to attack a port and initialize the port battle. those are quite fun tbh.
Mate sorry to hear it. . but in a previous topic the devs asked for proof like a screenshot . so if you still have a screenshot of the aggie you should be getting it back
i had the same issue at first. but then i went to the steam store. and hit their aviable dlc it wasnt there aswell. so perhaps this link will help
https://store.steampowered.com/app/1307440/Naval_Action__HMS_Victory_1765/