This assumes you are already logged in as the Admin user and are logged into the AdminCP logged into the AdminCP.

• Be sure you've got your user groups set up the way you want them before enabling subscriptions.
• Be sure you've got your payment gateway set up before enabling paid subscriptions.

 
Go to Subscription setting pages: in Admincp, click on Settings and select Subscription Packages, click on Settings tab:

Settings:

• (1) Enable Subscription Packages: Set to True to enable or False to disable subscriptions. (Default is False)
• (2) Subscription on registration is required?: Set to True to require a subscription choice on registration or False to not have subscription choices on registration. (Default is False)