How do i sell stuff on the shop ive done it before but i fogot please heallp

I think you mean Market. You to to ''Shop'' at the top, scroll down and at your left you should see your ''Activated and ''Deactivated''. You can click either of those and look for the item you want to sell, at the top right of the item it should say [Edit], press that, add a price and voila, you're item is on the Market, hope that helps!