You can use the multi reference field to make a collection of links inside your collection.
Regarding HTTP / HTTPS - Depends on your publishing preference. If your site is published on https, it is always better. But your domain provider might not allow that, so you’ll have to use http.
Hi. I just to make sure that this is the best solution… so under Branding > Studio Ongarato in the post there is Kate Robertson as a link (that doesn’t work currently) which is how I would like it to appear but with obviously the link working to Interviews > Kate Robertson. Am I better to manually create a link like I have or use the multi reference field - will this achieve the same?