how do i reset my apple watch password?

On your watch navigate to Settings-->Passcode. From there, you can change your passcode or turn off passcode. Both options will require you to enter the current passcode.

If you have forgotten your passcode, and you cannot reset from the Watch app on your iPhone, you will likely need to reset the watch manually. For more information on this process see this article from Apple Support:

Reset the passcode on your Apple Watch - Apple Support: https://support.apple.com/en-us/HT204567

Hope this helps!

Try this;

Press and hold both the side button and Digital Crown for about 10 seconds, then release both buttons when you see the Apple logo.Wait a few seconds, then hold down just the side button for about 20 seconds or until the “erase all settings” prompt shows up on the screen, then click it, then click the green check button.

Unpair and erase your Watch

The OP can't get into settings because the watch is unpaired.