Your iPad needs more that just the app.
Here are the requirements needed to use the Fitness+ app and Watch with a iPadOS compatible iPad.
Your iPad needs to be updated to the latest iPadOS, that means iPadOS 15.2.
Your iPad is too far behind in iOS/iPadOS upgrades/updates.
You need a compatible Watch ( series 3 or later ) updated to its latest watchOS version.
No options
The Fitness+ app will ask to automatically link the Watch to your iPad/ Fitness+ app, after the download of the Fitness+ app from the iOS App Store.
See the iPad/iPhone instructions here below.
How to start a workout.
Tap the link below.
https://support.apple.com/en-us/HT211923
Also, make sure all connected Apple devices are using the same Apple ID/password account information.
In addition, there is no TV mirroring of the Fitness+ app, using iPad, currently.
Currently there is no direct AirPlay/screen mirroring from an iPad to any other compatible smart TV or smart device using AirPlay2.
Apple, currently has ONLY made the mirroring/AirPlay 2 feature available to owners/users of an actual Apple TV box.
Best of Luck to You!
