Only group Leaders and group Owners can add and remove members. So, if you are the group leader/owner you can go to the Members tab of the group and find the member that you want to remove, click on the sprocket icon dropdown and click on Remove from Club.
If your group leader is AWOL please let us know at help@thetechtribe.com and we’ll get that sorted for you.
If you are looking to replace the member that you are removing, click here for more information on that.