We have included the instructions from the XDAdeveloper forum below. install at your own risk, all credit to MWisBest:
How-To1st FML Flash:
1. Do a backup in recovery and (optionally) backup apps with Titanium Backup or something similar.
2. Factory Reset in recovery (wipe data (NOT /SDCARD THOUGH), dalvik-cache, cache)
3. Wipe /system in recovery.
4. Flash ROM in recovery.
5. Flash GApps in recovery.
6. Reboot, and be patient. First boot takes a while.
Subsequent FML Flashes, unless otherwise instructed:
1. Do a backup in recovery and (optionally) backup apps with Titanium Backup or something similar.
2. Wipe /system, cache, and dalvik-cache in recovery.
3. Flash ROM in recovery.
4. Flash GApps in recovery.
5. Reboot, and be patient. First boot takes a while.
NOTE: You can probably get away with just wiping the 2 caches without wiping /system, however if any issues occur please re-test with a /system wipe.
Flashing the TWRP .img:
For this you can either use fastboot or the Flashify app, however I'm not going to delve into the details of that as it's really more deserving of a separate thread to fully explain.
Latest Build
LOLLIPOP INFO:
These builds are very early! They aren't daily-driver-stable, but they are progressing extremely fast. They don't include the usual FML optimizations either, but they are surprisingly snappy already...
They are EXTREMELY MINIMAL! Not even SetupWizard is included. I used the PA GApps, "Nano", as the base for it.
Known Issues:
- EXT4 ONLY CURRENTLY! F2FS will be OK for the next build though!
- Stock Camera app isn't working yet. Aftermarket ones, such as Camera ZOOM FX, might work however.
- Mobile data and MMS, isn't working on (at least) the LTE Galaxy Nexuses, however phone calls and text messages should be OK.
- Various other things I'm sure are lurking.
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