First off you need to be rooted and have Clockwork Mod flashed. If you need to root or flash ClockWork Mod you can search this blog for the tutorial.
Step 1: Download Virtuous Prime ROM [Official Thread]. We aren’t linking directly to the file since the developers may update the ROM and its download link.
Step 2: Place the .zip file directly under /sdcard on your Transformer Primes internal storage.
Step 3: Shut down your Transformer Prime. Once it has completely turned off, press and hold Volume Down + Power buttons until you see white text in the top left corner. At this point, you must release both buttons and press Volume Up. You will now boot into ClockworkMod Recovery.
Step 4: From the main menu, take a nandroid backup.
Step 5: From the main menu, select wipe data/factory reset.
NOTE: This will reset your device to factory settings, meaning all personal data will be deleted from device.
Step 6: Navigate to install zip from sdcard > choose zip from sdcard > [file you transferred in Step 2] to flash the ROM to your device.
Step 7: Once flashing is complete, select reboot system now from main menu.
