What is difficult then
or not clear ?
I suggest you do the following:
a) on your desktop, extract the .zip.
b) delete the overclock_14.ko file (you can redownload the zip if you want to go higher, for now let's say you only want 1.2Ghz).
c) rename overclock_12.ko to overclock.ko
d) copy to phone on your SD card.
e) open terminal and execute:
If you don't have a terminal, use Script Manager and create a script with the same text as above and execute through Script Manager (although Android Terminal emulator works best).
If you want to go back to stock for whatever reason: