Create a couple of buttons...sleep 30, sleep 60, cancel

Now make sure those buttons are set as "Use Device Default" RF 1 way trigger codes.

Now on the 30 button place the "system off" system macro(stored on the XP8)
Use the macro editor and actually create a macro on the sleep 30 button

You will see on the bottom of the System macro selection page a Timer function, you will select in xx minutes and xx seconds, set it for 30 min and now drag the system off macro into the window

Now create a system off macro on the sleep 60 button but set the run this macro in 60m and 00s

Now on the Cancel sleep button, place 2 system macros of cancel the 30 min and 60 min

Once you see how it works you will understand it a bit more