Join request problem creation ... problem :(

[Goodman_2020]

Hi,

I created a paid subscription (premium member)
I want to give the possibility at the begining for register users to test the advantages of being premium emmber during a week.

So in my custom usergroup (premium member) in public group settings, i said "yes" to the 2 first options (Public (Joinable) Custom Usergroups / Can override primary group title/markup).

Result: it created a neww options in usercp, where the registered user can do a join request. Till now, that's ok. Except that when i test with a test member and click on "join the group" i join directly the group, whereas i would like that me (the admin) i can chose to validate or no the request.
But when i click on "join requests" there is nothing, so i can control the permissions i give for that.

1) What to do to do what i want to do? maybe i did something wrong...

2) Secondly, they could be "premium member" only for a week, so i would like to control that, reversing the permission after a week, (manually for each member) How can i put them back in the original usergroup they had when their "test period" ends?

Thank you