Hi @hocngoaingu2586,
Welcome to the community!
In order to have more than one concurrent meeting, you need to create additional users under your Zoom account. You can either do this on the Zoom website, or via the Zoom API.
Once you have more than one user under your account, you will be able to schedule meetings for your users. Each user can have their own meetings, and you can join/manage them using the single key/secret.
Tommy explained it well here: Concurrent meeting in same time with different api key and secret (JWT app) - #4 by tommy
Thanks,
Alex