A waiver only reaches customers once it's attached to an activity — templates on their own don't go anywhere.
Open the activity in Settings → Activities (works the same for Tours, Trips, and In-Person Courses) and go to its Waivers & Medical Forms step.
Under Attach Waiver, select one or more waiver templates from the dropdown. Every participant booked into this activity will need to sign each one.
Optionally add a Link to Medical form — an external URL you'd rather link out to than rebuild as a template.
Click "Next" and save the activity as usual.
Good to know: You can attach more than one waiver to a single activity — for example, a general liability release plus a separate medical form. Customers sign each one in turn.

