RouteOS: how to run script when opening login.html in hotspot?

Question

Mikrotik

Hey!
Mikrotik is configured with a hotspot, when connected, the user is shown a page with a login and password.
From this page there is a redirect to the page with information, then back to the page with the authorization form, when redirecting, the get-parameter (flag) is passed, at this moment it is necessary to execute the script that will open the hotspot for this user by the flag.
How to call a script on redirect?
Is the logic correct? Is it worth organizing a radius (there are very few users, the load on the router with rules and tables is minimal, and it seems that you can get by with only the resources of the router itself)?
Thank you.