You can access your passes in two ways.

Your pass link was emailed after you purchased your Booster Membership from hello@gobound.com subject York Dukes Booster Club Memberships. Just click the OPEN YOUR TICKETS Button from the email (image below)
You can download the Bound app to have easy access to Your Tickets With These Directions. Make sure you sign in using the same email you used to purchase your Booster Club Membership.
Click here for iPhone link or Android Link if you have not downloaded the app

Then Follow to Access Your Pass From The App

How To Use Your Pass on Game Day!