Subscriptions typically include access to classes or appointments. But they can also include access to on-demand content.
This can be done in one of two ways:
Include access to your entire on-demand library; or
Create another special type of subscription called an 'on-demand subscription' that includes access to collections of on-demand content -- then link your regular subscription to that on-demand subscription
To include access to either, locate the subscription you'd like to add on demand benefits to > click the dropdown menu to the right > click Edit
Scroll to 'What this subscription can be used for' > click the dropdown menu for 'On-demand subscriptions that are linked' > choose which subscriptions or the entire on-demand library > Save