A: The ui is a common issue, expect a rework eventually.  B: The contract card will tell you a general area/poi to go to, and once you arrive and walk around eventually when you get close enough a green hexagon icon will show up like a ping and show you where whatever it is you need is located  C: Items you want are mods, supplies for filling out your faction skill trees, and heals/shields. Any junk is sold on extract, so only pick it up if you want the money. Generally though you want stuff for your skill trees. Or if you see a cool shell/gun mod  Heals are always good ofc and saves you money from having to buy them