Arming DSC

Hello All

I think I am lacking a little understanding about my DSC system; which I have realized as working on my HSTouch HMI. This is more about basic understanding how others implement their systems?

What exactly is the difference between:

• Arm Stay
• Arm Away
• Arm Zero Delay.

I have upstairs PIRs set as zone definition 37.
I have downstairs PIRs set as 05.
I also have external doors which are set at 01 or 02 (delay 1&2).
And internal doors as 26 (indication only)

Thanks
Chris