Make sure the wheel bearings and spindle are greased and packed.
Tighten down the "Castleated "nut tight enough so that the wheel just spins freely and inset the cotter pin through the accesss hole to prevent the Nut from "Backing-Off".
It is what you would call at "touchy- feely" but yet a secure adjustment.
There should not be any wheel wobbly of play.