I bought the Park tool pencil style tire gage. It came with a Schrader to Presta valve adapter and on their website it says it can be used to check pressure on Presta tubes. I can't get it to work,does anyone know how?

Loosen and burp the Presta valve nut. Screw on the adapter. Check the pressure, Remove adapter and tighten valve nut.

Excellent advice,thanks. I wasn't pushing the gage firmly into the adapter,when I did it works.