To verify the number of allocated and used licenses:
- Navigate to Setup->Build->Installed Packages
- Verify the license status, expiration date, allowed and used licenses
If the Allowed Licenses column says Unlimited then you are either in a sandbox org, or you have a site license.
If it shows a number, you can assign licenses to individual users by:
- Clicking the Manage Licenses link next to the Decisions on Demand app
- Using the Add Users and Remove Multiple Users buttons to modify the licensed users.
You can also click the Remove link next to individual users.