Certification CA and users account expiration

[GiovanniG]

Hi mates, I've experience building SSTP server with Mikrotik, and I would test also this solution.
I would know if there is a guide how to generate a CA certificate (using Let's encrypt?) by the GUI and eventually how to scedule an automatic renew..
I wouls also now if there is a way to set a date/time limt for the user, when expired the account can't be used more. Possible by the GUI?

Thank you for your kind support