Hi David,
In order to create a group, you need to add a ‘hosting’ skill to your profile. Doing so will change your role to ‘host’ in the system, which gives you this extra function.
I’ve added the hosting skill ‘managing events’ to your profile, so you should now be able to add your group.
You can learn more about how to set your group up here: How to follow, create or customise a group
Shout if you need a hand 
James