I downloaded update, try to place in root folder(using Astro) but it wont let me. is there any place out there giving step by step?
Which update? Are you downloading the clockwork or the SPRecovery update?
First things fire -- make a Nandroid backup of your phone. To be safest, copy it to your computer.
If it's the SPRecovery update you need to extract it and place it in your Nandroid folder, then boot into recovery, restore, advanced Nandroid restore, pick the froyo nandroid, then tell it to restore.
However, you MUST clear your system and data caches first.
So, a step by step -- mount your SD card, extract into your Nandroid folder, reboot phone into recovery, made a Nandroid backup, wipe system/data caches at
least twice to be completely safe, select advanced Nandroid restore, pick the FroYo Nandroid, do your restore (I select everything except recovery, but that might be overkill), reboot the phone, wait for it to reboot, run through the phone setup crap, wait for it to sync, enjoy your FroYo goodness.
You may want to update your baseband as well. If you do, I posted a link to Pete's all-in-one baseband update a little earlier in this thread... or you could look it up in his Bugless Beast subforum here.
I don't use clockwork so I have no idea how to run it. I'm sure someone else does.
I also think there's a FroYo install thread somewhere on here that would answer all your questions.