Hello Skyfire and Welcome back to the game!  You can find assignments in the Alpha terminals such as TMA, Asintec Alpha, or ICS Alpha.  Click the assignments tab and check what is available to you based on your current relations.  Also you will want to "grind" the faction that you want to pilot.  IE:  I pilot Nuimqol so I would grind Nuimqol faction for that type of ammo.  Good luck!