For the front shocks the top of the shock goes through the hole in the inner fender well when you buy new shocks it should come with the necessary hardware for the top.Basically going from the top of the shock down it`s nut,washer,rubber grommet,fender well,rubber grommet ,washer. As far as the back I`ll have to look through my parts for an old nut/bolt to tell you an exact size maybe someone else will chime in with the answer. I used a couple of grade 8 nuts/bolts from the local hardware store for the upper rear just can`t remember the size off the top of my head.
If you didn`t already know this compress the shocks down then tie them with some wire to hold them in place. Once you get them in bolt the bottom and put the washer and grommet on first for the fronts then release the wire and they will expand up into place. It`s a heck of a lot easier than pushing them down by hand and fighting them. Hope this helps!
Edited to add: compress the shocks and wire them down if you cut the plastic strap before putting them in like I did
either way works top down or bottom up. Sometimes I just gotta learn the hard way!