How do I tell how many steps I have on my Apple Watch? Does it have pedometer?

It is not a pedometer per seem but it acts as one. You should calibrate the watch according to these:

Get the most accurate measurements using your Apple Watch - Apple Support

Calibrating your Apple Watch for improved Workout and Activity accuracy - Apple Support

Then you can see your steps using the Activity app:

Use the Activity app on your Apple Watch - Apple Support

Go to the Activity app and swipe down partway. You'll see the number of steps you've taken so far today.

If you want a complication that shows steps, I believe you'll need a third party app. StepsApp is one I have used.