under dash wire harness

Although you don't indicate what kind of car you have, generally there are large clips along the bottom of the dash in which the loom will lay. To the left you will see a metal tab with a hole in it- this is where the fuse block screws to. The short end of the loom goes to the left and down the kick panel. The long end of the loom goes to the right, through the large clips, over the column and out towards the glove box. Hope this gets you started.