Root new rom, HELP PLEASE!

[arm1987ada]

hi,
i have a problem with installing new rom on desire.
well, now I have miui and I want to install this rom [ROM] HTC Desire GR Edition |2nd November 11| Ginger Sense 2.3.3 |ROOT|BRAVIA|STABLE| - xda-developers

i wasnt installing miui so i dont know how to change it to new one.
can somebody tell me what i need to do or give me some link where it is all detailed because i am a total begginer with that


one more thing, can somebody explain me what is this and how to do it.
"Bravo CM7 r2 hboot: Wiped ext3 or 4 partition (for APP2SD), 512+ MB - Dalvik-Cache is on the SD-Ext"
dont laugh, please

 

[Hadron]

Re. Hboot, reboot the phone while pressing the "volume down" button. You'll get a white screen with little green androids at the bottom. See what it says at the top of the screen. If it says S-On then you have a stock hboot and can forget about this. That ROM works with a stock hboot as well.

You will need a ext partition on your sd card. To see what you have, install Quick System Info and see what it says your a2sd storage is. Titanium Backup can also tell you this (bottom of the entry screen).

If you haven't got a partition, or it is smaller than recommended (total size, not free size) then read the root memory faq, linked from the All Things Root Guide sticky post, then we'll be happy to help you put one on.