I think you refer to Load Testing console, don't you?
Think time is the time between two consecutive user requests in a script, meaning that even if OpenScript is a robot, you try to simulate real user interaction, where this user performs some tasks on a page (entering data, drinking coffee, and so on)
Delay time is the delay (the time) between two iterations of the same script ie the same business process to represent the number of processes you can execute in 1 hour for example.
You should ask the business owner to understand how fast users executes ONE business process and how many business processes they are supposed to execute in one hour (for example). Then, you try to represent this given load in the console meaning reaching a number of transactions per sec / min or hour.