Does a personal loan function similarly to an overdraft, or does it involve regular cash repayments?

Personal Loan depends on how it is structured. Usually it is a time-bound loan with regular payments (of Principal amount + Interest). Others structure it on a moving utilization, i.e. you have say $10,000 credit limit (for your personal loan) and whatever you use, is charged to you on a daily interest basis. You are expected to pay a minimum charge (principal amount + Interest) at the end of each month.

Most of the time a personal loan can be though of nothing more than a credit card limit that you have, without the card itself. Same concept.