rsvpBOOK has 2 versions of the Admin Dashboard.  Which one do you have?

This example shows 2 "empty" groups - each group is a purple row with a Group Number in the green column, labeled Group Order.

As you add Groups, they are numbered in increments of 20, starting at 20.  Increments of 20 provides "insert" room for inserting new groups or changing the display order of existing groups.  To change the display order of groups, change the Group Number(s) so that their sequence matches the final display order of your groups.

1. In this example, to have the group (Group Name 2) display BEFORE Group Name 1, change the current group number (80) to, say, 55 (any number less than 60)
2. Click any Re-Order button on the page (it doesn't matter which one you click)

View this document: How do I change the display order of sessions?