How do I use Touch ID on my gen 10 iPad once I have set up my fingerprint

I believe it's the thin power button and it's a light contact with it without pressing the button down. Not much similar to how previous iPhone/iPad home buttons used their fingerprint sensors with a physical or haptic button.

The iPad User Guide describes the straightforward process of setting-up TouchID:

Set up Touch ID on iPad - Apple Support

By default, TouchID will be used as an available alternative to entering your iPad Passcode - although you can alter some settings that will disable or enable TouchID for some authentication tasks:

Settings > TouchID & Passcode > [Use TouchID For]

• iPad Unlock
• Wallet & ApplePay
• iTunes & App Store
• Password AutoFill
• Other Apps (these will only be listed for Apps that are compatible with TouchID)