How did the colonists get on the ships to dump the tea?

They boarded 4 ships at that were in the port. On one ship they hit the guard over the head and knocked him out. On the other 3 they had no problems with the guards. They were NOT dressed as Indians and they didn't care who knew who they were. They were smugglers of Dutch tea that would have cost more because the British tea would cost LESS because the tax was made LOWER.