Once you have created 1 or more Code X groups as outlined here you can now choose if you want to give users the ability to view certain Code X groups from UCP which will let them manage a few things such as
Start a Code X group
Stop a running Code X
Change the Checkin of any member status too safe or unsafe.
View reports on past executed Code X's
Navigate to User Manager module in FreePBX and edit the Group or User that you want to give permissions to for Code X groups.
Click on the UCP Tab
Click on the Code X Tab
From here you can pick which Code X groups the user or group have permissions to and submit your changes