Please check this document for a detailed lmadmin installation guide with screenshots.

Starting as a service

The Windows lmadmin installer will offer you to install lmadmin executable as a service. It is recommended to enable this option as it will ensure that lmadmin is always running and can serve license requests from IDA clients.

If you used 'lmgrd' instead of 'lmadmin', you'll have to manually instruct Windows to register 'lmgrd' as a service.