How do I restore my phone using my iPad?

If your iPhone has iOS 15.2 or later installed, check out this link→How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support

Otherwise, see this Apple support link→If you forgot the passcode on your iPhone, or your iPhone is disabled - Apple Support

Or watch this companion video ⬇️

After restoring the phone using one of the methods above you can restore your most recent backup.

You don't. You will need access to a Mac or a Windows 10 PC with iTunes.

If you got to the point of asking for a password it is the backup password, not the phone passcode.