Usually for early entry (which opens around half-yearlies), most unis request students to apply for early entry. If they're successful, they move onto the interview stage. At this point, it's up to you to persuade them as to why you should be given the chance for early entry into the uni. Normally, they also ask for your mid-term results or w/e else. Then yeah, if you're successful with the interview, you move onto the next stage, which is as described above.
Try not to worry about it before exams though, leave all this mess until december-january. It's the worst 2 months ever!