http://e55lzoju6enqswtvm66sk3uqukcin3377ehgiorplj4d7qyssipls4yd.onion/en/blog/what-is-coinjoin-technology-in-bitcoin-mixing.php
What User A first has to do is find a platform with other people (Users B, C, D) who also want to make a purchase in Bitcoin. Users A, B, C, D agree to join their Bitcoins together in one big transaction on that platform.