On my Apple Watch how do I know how many steps I have taken on an Outdoor Walk

The activity app on the watch records the steps. You can also look at the fitness app on the iPhone. This is what it looks like for someone just sitting around so far today 😧

To get good results, you need to calibrate the watch (help it figure out how big your steps are)--basically you need to walk or run for about 20 minutes for the watch to do its calculations. Details are here:

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

It automatically resets each day.

The default Apple workout app does not have that info.

They lump it in your total steps for the day. They log distance, time, heart etc

There is nothing to reset.

However you may be able to find a 3rd party app that does what you want.