You will find the corresponding option inside:
Dashboard >> Reign Setting >> Community Settings >> Advanced Setting
You will find the following options inside it:
Member Per Page: Here you can manage the number of members to show per page.
Group Per Page: Here you can manage a number of groups to show per page.
Select xProfile Field: Here you can select an xprofile field to show on member cover image header.
What’s new activity lightbox: Disable What’s new activity lightbox.