what ever you do dont glue the hardwood to the concrete as the expantion rate is difirent.that will cause your wood to pull apart or crack.
if your slab is on the same level as the rest of the house use a leveling compound on the concerte.Then put down plywood or partical board first then attach the hardwood to it.if ther is a stepdown into the room use a 2x6 or 8 ect.what ever will bring you level.
cut your board to follow crown or use the leveling compound (thats the easiest)then the plywood.keep in mind the thickness of the plywood and the hardwood when you place the 2xs