Host & presenter
A host owns meeting rooms and can make an unlimited amount of rooms. A host can have one meeting at a time. As a host you can show a meeting in ‘presenter mode’. Which means your guests will only be able to follow what you show. Read here how you can do that! So a presenter is actually a host who has enabled the presenter mode.
A guest is someone you invite to have a meeting with, you can invite multiple guests. Guests don't need an account, nor need to download anything to join the meeting. They can interact, edit documents or follow the meeting.