ok so if i want to win $100 i "Stake" 100. So I get 200 back if I win the bet? Or if I lose the bet and the lay odds are 90, I have to pay 9,000?

How do I know my odds for me to win on a lay bet? Do I just get the back odds when I win the lay bet? Are there no odds for my win for a lay bet? So effectively I just back what I stake plus my original bet? So its a 100% return? (E.g bet 100, Return 200, Profit 100)?