The link to watch a livestream you have purchased can be found in your original receipt email (title starts "Thank you for your purchase"), and any reminder emails the event has sent out. Those will contain the line,
"Your purchase includes virtual access to the event. Please follow this link to watch."
Clicking "this link" found there will take you to the virtual access page to view the event's livestream or video.
Alternatively, the link also is provided on your Passage account's tickets page. To get there, log into your account at app.gopassage.com, then go to My Tickets.