You can manage multiple gyms with the same account. Note that you will need the appropriate account plan that supports the amount of gyms you wish to manage, before your trial expires.
A new location can be added from the dropdown that appears when you click / hover over the gym name in the header. Click on the "Create New Gym" button, and you will be sent to the gym creation form.
Setting up a new location is similar to the gym creation process you did when you set up the account.
To switch between location, hover / click over the gym name in header, and click the "Select" button next to the name of the gym you wish to manage.