Freeze or ice till ready to use. DO NOT SALT. That retains the moisture and they will rott
You can either flesh scrape them or pressure wash to remove any meat or fatty tissue. If you don't have a presure washer it's fairly easy to flesh them out.
First of all keep them on ice or just freeze them till you are ready to work them. This keeps the bacteria and smell down.
When your ready to flesh them get a 2x6 or 2x8 and secure it about waist level. get a 5 gal bucket of warm water with about a 1/4 cup of bleach in the water. Dip the end of the skin in the bleach water to make sure it's not to strong.(you can bleach out the color) You want it just strong enough to kill bacteria and help the fish smell. Dip the whole skin in to remove some of the slime then place on the 2x8 flesh up. The rough skin will hold to the board while fleshing. You will notice a center line the entire length and some zig zag cartalege rings. To flesh it's best to use a slightly dull blade and work from the center out toward the sides, scraping in the direction of the cartalege lines. The dull blade will push the flesh off instead of cutting into the skin.I work one side from center out then turn it around and work the other side from center out. When fleshed,dip it in the water again and let hang on the end of the board for a few minutes.
When you get a few done just take a piece of plywood or board and staple them flesh side down. I use an air stapler but any stapler will work. Start at one end then strech slightly and staple the other lend ength wise. Then go down one side and pull a slight bow in the center line,while stapling. then as you stretch and staple the other side the center line of the skin will be straight. Your staples should be as close to the edge as possible or the skin will curl over it when dry. And place the staples no more then an inch apart.
Let dry for several days and then just cut inside the staples with a razor knife. It will peel out like a sheet of paper. Wipe both sides with acetone to help remove oils that have leached out. Then roll up and place in a zipp-lock till ready to use.
As far as the scales I generally remove the large center line scales. this helps when fleshing and I generally use the upper and lower parts on each side of the center scales. this will give you 4 skins per fish. Two darker upper sides and two white belly skins that will turn transparent when dry. The bone flake will stay attached very well, no need to remove. If you use black leather dye to darken the wood befor aplying the skin. in will help bring out the contrast with the white bone flake.
I have always used sinew glue to apply just because it tends to really suck the skin to the wood and is protien based as well. I warm the glue and let the skins soak till pliable then apply and wrap with strips of the fiberglass drywall tape. This allows the skin to breath and dry faster. Just dont wrap to tight,or it will leave lines in the skin.