In the receipt email you received at the time of purchase, there is a box labeled "Download items" / "Download tickets," where you can click to proceed.
In the next step, you can see the QR code for your tickets. This serves as your ticket and grants access to the event itself. However, this format is not suitable if you want a print-friendly ticket. Instead, scroll down the page until you see the following box with the text "Entire purchase as PDF":
Click on "Download all items" to download the tickets to your computer, and they will be saved in the location where your downloaded files are usually found.
Now you have the tickets as a PDF and can print them out.
If you don’t have your own printer, for example, the city library may provide a public computer so you can access your email and download tickets to print for a small fee.
Just remember that the ticket is a valuable document, so double-check to ensure no ticket is left behind in the printer.