Understanding Interchange trades

Hello. I was wondering if somebody could help me walk through a trading roundtrip step-by-step to better understand this new way of trading.
I’m especially curious about the destination address of funds for each trade. Is it true peer-to-peer or is there some sort of contract in between ?

As a taker for example:

  1. I take a an order to buy ETH with BTC (0.1 BTC for 2 ETH)
  2. The order is submitted to miners along with 0.1 BTC worth OL collateral + extra OL to cover mining fees.
  3. The interchange client (app) sends my bitcoin to sellers address. My Bitcoin leaves my wallet and goes directly to seller. I pay BTC network fees.
  4. Miners confirm my transaction went to seller successfully and release my collateral minus fees.
  5. I receive 2 ETH in my ETH wallet directly from sellers wallet. Seller payed ETH network fees. Miners check and release sellers collateral minus fees.
    OR seller does not fulfil order, seller loses collateral, some mechanism is returning my BTC recovered from OL collateral ??? Or I get the collateral instead of my original BTC ??

As a maker:

  • Where is the orderbook stored ? You need to iterate over all blocks to reconstruct the orderbook entirely or is it simpler than that ?

Is this how its going ? Can somebody clarify my attempt a little ? Thanks in advance <3
So trades happen truly peer-to-peer and OL network act as the validator and keeper of the collateral. Correct ?