I have been able to successfully obtain about ten different little things in my inventory, that says you can use them to gain favor with your companions.

It also says that you have to have learned something to be able to use them (such as Weapon Rank 1).

Do you have to train in these things or do you need to train your companions?

Im just not getting this and im about to throw them all onto the market to just make some extra credits.

Any help would be great.