How users collectively sign a transaction in a multisig scenario?

Say there’re 3 people (A,B,C) involving into a 2 of 3 multisig scenario. If A & B agree to sign a transaction, what steps they should take? My guess is:

  1. A creates a transaction with the multisig address, signs it with A’s private key.
  2. A gets the raw transaction above, somehow (via email or something else) manually sends it to B.
  3. B signs it and broadcasts to the whole Bitcoin network.

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