Thanks for using the dev forum!
If you are trying to join a meeting you can simply provide the UserName and Password. The Username is just the name you would like to display in your meeting, the meeting number can be obtained from the meeting settings on the other device in the meeting or in the invitation information.
If you are trying to start a meeting you need the UserName (same as before), UserID (This is the user’s Zoom email address or Zoom UserID), and AccessToken. The AccessToken is a token that must be generated through the RESTful API: https://marketplace.zoom.us/docs/api-reference/zoom-api/users/usertoken. The MeetinNumber will be generated for you in this case.
The easiest way to get to the main screen is to start a meeting on another device and get the meeting number then provide it to the SDK and click the join button.