First go to the product you want to put a journey link in, Catalog → Products →

Edit product

Once you have selected edit scroll down until you find ConfigWise and click.

Scroll down until you find AR Links and change the AR Deeplink url to Journey link(1), Put the journey link in the Override AR Base URL textfield(2), Click on Save to save your edit.

Once you scan the QR-code you will be redirected to the journey page.