BuddyPress.org

I am new to WordPress and Buddypress. I have a couple of items I am struggling with and would love a little direction.

1. In Buddypress, when you visit a group that is private, you receive a default message that says “This is a private group. To join you must be a registered site member and request group membership.” I would like to add a button directly below this message that says “Register”. This would need to be connected with the default message in some way so that the register button appears every time (and for every different group) the default message is displayed. I tried before but it seemed to connect the button only to one particular group. How can I go about adding this to the default message and what file and where in that file would I edit such a thing?

2. Once they press the button to register, how do you get them to redirect back to the group they were originally linked to?

3. In Buddypress, is there any way to turn off the public, private, or hidden options when creating a group and just make all groups private automatically?

I would really appreciate any assistance. Thank you.