If you would like to allocate a meeting to a team, you can do it at any time - when creating a meeting, before you join one, or after you've completed it. It's up to you. Note that you can do this only if you are the host.

Simply choose a team you want to add your meeting to.

Should you reconsider and wish to assign your meeting to a different team while disassociating it from the previous one, please navigate to the Meetings page. Click on the 3 dots menu next to the specific meeting, choose to see "More details", and then simply choose another team you would like to relocate this meeting to.