One user can host one meeting at a time. Even if you can get Zoom to schedule 2 overlapping meetings, if one meeting is active and you go to start a second meeting, you’ll be prompted to cancel the other meeting before continuing.
With Business and Enterprise accounts, a user can be given permission to schedule meetings for others, but can still only host one meeting at a time for any individual user.
With your Pro account, you can have 2 or more users (up to 10), and each can host meeting at the same time.
Each user you add to the account can schedule and host their own meetings, independently of each other, but if they are not assigned their own license, they will be Basic users and limited to 40-minutes when there are 3 or more joins to the meetings they host. If they need those Basic limitations removed, then you would need to purchase additional licenses and assign each user a license.