Can someone tell me the entire process of a trade and how it works.

i dont understand what middlemen do. can someone please give an in-depth answer? because im looking to sell my steam account.

You both give your account info to a middle man
The middle man then changed the email (temp email) and password
when both the peoples account have a temp email on them and the password + security questions have been changed then the middle man will then swap the accounts

The middle man will then stay in the trade until both people have finished changing their shit (email, pass, security questions etc)

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You give them a password to say the acc your selling, then they check it out, the buying then send the MM the money and the MM gives money to seller and acc to buyer