Providing references for job interview - Who to add?

Given my limited experience in the industry, how close should my relationship with them be?

Close enough that when they get a request from a hiring manager to say nice things about you, they don't respond with: "Whuh?". In other words, you should be fairly close, at least closer to a friend than a casual acquaintance.

Would it be acceptable to use my university examiner as a reference in lieu of a previous boss?

If you've never had an internship or full-time job before, then you pretty much need someone from school for this. If your university examiner thinks highly of you, you can put them down. Otherwise, you can think of other professors you had a great relationship with.

References is just one of many reasons why software engineers need to start building deep relationships ASAP - This is something I, and most engineers, realized far too late. To not fall into the same trap we did, I recommend this: [Masterclass] How To Build Deep Relationships Quickly In Tech

Here's another good thread about references: "Can you please suggest me any names from Meta to put as references?"