Okay kiddo, so a uni lad is a term used to describe a young man who is currently attending university (where people go to study after high school). The term "lad" is used to describe a boy or young man who is friendly and outgoing, and likes to have fun and mess around with their friends.
So, a uni lad is basically just a student at university who likes to have a good time with their buddies. It's important to remember though, that university is a place for learning and growing, so while it's okay to have fun and make friends, it's also important to make sure you're putting effort into your studies and becoming a responsible adult.
Hope that helps, little one!