COURSE 2 - 8.2.4. CoinJoin: 3rd step
QUICK INFO:
All other partricipants except the leader and the last one to sign: in Electrum, "Tools" > "Load transaction" > "From file" > selects the partially signed Bitcoin transaction he received by the last participant who signed it > "Open" > "Sign" > write/paste password of Electrum wallet > "Ok" > "Export" > "Export to file" > "Save" > "Ok" > sends the CJ transaction with his signature (but whose status will be "Unsigned" until the last signature is made) to the last participant to sign according to the signing order agreed.
3rd STEP: according to the signing order previously agreed, all other participants receive the CJ transaction by the last participant who signed it, sign it themselves and send it to the next participant for signing.