For single-user license users, there is no limit to the number of instances that can be opened simultaneously on the computer.
For concurrent-use license users, each seat acquired from the server permits three instances of the software to be opened simultaneously on the client computer. If a fourth instance of the software is opened, an additional seat will be acquired from the server. This will continue for every three instances that are opened on the same client computer until no more seats are available. Any additional seats acquired are returned to the server as soon as the additional instances are closed.