With your android smartphone:
Unlock your phone.
Hold your phone over the terminal until you see a blue check mark on the screen.
With your watch:
On your watch, open the Google Pay app.
Hold your watch over the contactless payment terminal until you hear a sound or feel vibration from your watch.
When paying within apps:
With Google Pay, you can check out in apps without having to enter your payment information. Shop, order takeout, or get tickets with the press of a button.