@kenosis, there are many topics that explain you step by step how to do it, here's what i did to move from Pulsar Helix to 2.1 rooted:

1. install drivers for your pc and adb.exe (you get adb.exe from latest android-sdk)
2. download RSD Lite and install it
3. download 2 SBF files: 2.1 DACH FULL SBF (02.34.0) and SHOLS_U2_01.14.0_recovery_only.zip
4. flash with DACH FULL, THEN SHOLD recovery_only using RSD Lite.
5. when using rsd lite you'll get some errors, that's why you have to use COMMAND and not interface to flash phone.
6. after you completed both steps, use milestone_root.zip > upgrade.zip to gain root access if you want it
7. win