Hello oswald250,
The article you visited shows to put the iPad in recovery mode for a forgotten passcode. Once in recovery mode, the computer should then recognize the iPad, and offer to restore the software.
If you forgot your iPad passcode - Apple Support
"Step 3: Put your iPad in recovery mode
- Get ready by finding the button on your iPad that you'll need to hold in the next step: iPad models that don't have a Home button use the top button.
- Press and hold the correct button for your iPad while immediately connecting your iPad to the computer. Don't let go of the button.
- Keep holding the button until you see the recovery mode screen on your iPad, then let go.
- If you see the passcode screen, you need to turn off your iPad and start again."
If the issue continues, restart your computer and test with a different computer port, as perhaps that will clear up the connection issue experienced. Check out those suggestions here:
If your computer doesn't recognize your iPhone or iPad - Apple Support
Kind regards.