rooting htc desire hd 2.3

Hey guys.. i want to install coredroid v8 on my dhd.The problem is i don't know how to do it. How do i root my dhd running android 2.3.3 and i don't know how to backup apps too... To be frank Please tell me how to install a custom ROM in Dhd running 2.3.3 also tell me how to backup my existing ROM just incase something terribly goes wrong :):):)