Ok first of all your form have to be editable by rich client you can configure that on "form option", "compatibility". After that go on "Data" and select "User Roles" here you can configure a default group that have a standard access and an admin group wich have more access. you have to set your AD group like :
DOMAIN\group Name. You can check if your AD group is correctly configure if you preview your form and check on the right bottom of your window it will show you your current "role". Another Important thing to know is roles use the windows login not the SharePoint One. If you want to check another account you have to log off and the login with your other account or use another computer or VM.
When you are sure that your roles work properly on each control, you select manage rule and you set some condition like if User's current roles is not your admin roles then disable this control.
Hope it's help.