The wise ones in the house please guide me. I intend to act as a facilitator between a client that wants to sell a standard SUV to a friend of mine. Though I'm yet to link them up but they've been talking through me.

Please I need an advice on:
1. whom to collect facilitator fees from among the 2 of them ❓
2. Will the fees be embedded in the vehicle's cost ❓
3. What will be the percentage to be paid me as the deal facilitator❓
4. Will the percentage be based on the vehicle cost or will the facilitator fees just be any convenience sum ❓

Please help me out urgently