[XCSme]

Are the users registered in any way (e.g. have accounts)? You could check the login logs.

If not, you could also use something like UXWizz[0] to tag each individual session based on their user ID and then run a MySQL query to get the distinct ones within the last 30 days.

[0]: https://uxwizz.com

[KhoiUna]

Is it not free? Do I have to purchase a license?

[XCSme]

Yes, it's a premium self-hosted product. You can probably get a discount if you get it for personal usage and contact support.