Joists or sleepers?
Joists are installed upright, sleepers lay flat on the wide side.
If you are talking about sleepers, forget the insulation under the wood...it will flex with point loads and large people. If you are going to use sleepers use a 2x4 and nail it into the concrete.
For Joists you need a ledger board at the wall section to carry the wood upright, for those you can install a ledger board (like on a deck)and joist hangers with the foam underneath...and fiberglass if you want in between. I think fiberglass is just a srewup that got perfected....use some other blown in material for better results.
Hope this helps.