Delay is how long between the packet is sent and received.  This is also commonly called "ping" and "latency".

Set the number to how many miliseconds to delay the packet receive by.  Please keep in mind that this is in addition to the actual packet receive time by the proxy!  If it takes an actual 25ms between the server and your proxy and you set it to 200 the actual latency will be 225ms!

Jitter is how much the delay can increase or decrease by.  A consistent ping is unusual so having some jitter will make it look like a residental connection.  If you set the delay to 175 and the actual latency is 25ms, the latency will be 200ms.  By setting jitter to 50 (or 50ms) that means it can be anywhere between 150ms and 250ms.

Correlation means how the previous delay is correlated with the one that is about to be received. With 0 correlation it can be anywhere between 150ms and 250ms (using the previous example.) With correlation it will instead modify the latency to be closer to the previous amount so it does not jump from 150ms to 250ms back to 150ms.