Sorting raiders has a little bug, when you sort the raiders and then mouse over their name, it highlights in green the raider that was originally in that space. So for instance, if i sort by DMG right now, one of my archers is at the top of the list, but mousing over his name, still highlights the fighter that was in that position.
First click them in the inventory, then click an empty slot in the "Skills" section of the ability overview for your raiders (the button below the inventory button on the right)
 "Micrics"){kind=icon}
 "Logical Element"){kind=icon}
 "Idle Raiders"){kind=icon}
 "DuckLife 4"){kind=icon}
 "My Big Friend"){kind=icon}
 "NoNoSparks: Genesis"){kind=icon}
 "Steel meat"){kind=icon}
Thanks! MORE in the second part :3