This is a guide to flash Paranoid Android to the galaxy nexus, from the stock rom.
1. Unlock the BootloaderEdit
Install the android sdk and make sure that you have the correct adb and fastboot drivers.
on windows, navigate to the android sdk folder, and then to the platform-tools folder in cmd or powershell.
with \path\to\android\sdk_directory replaced with the actual location of the downloaded android sdk directory.
on linux, once you install the appropriate packages, fastboot and adb will be installed to /usr/bin, so there will be no need to navigate to a certain directory to use these commands.
Connect your Galaxy nexus to your computer, and boot it into the bootloader. You can do this by pressing both the volume up/down key with the power button as the phone is booting up.
On windows, in the cmd window, type
fastboot oem unlock
in linux, open a terminal and do the same.
This will unlock the bootloader of the device, and will wipe all data from it.
Install TWRP recoveryEdit
Now that the bootloader is unlocked, it's time to install a custom recovery. Custom recovery makes it easier for you to flash roms and do other troubleshooting activities. Go to http://teamw.in/project/twrp2/90 and download the latest twrp img file.
now, on windows, in the terminal window, type
fastboot flash recovery Path\to\TWRP\file.img
of course, you will have to change the last bit to match the actual location of the downloaded img file.
on linux, do the same in your terminal.
it won't take long to flash the new recovery.
Boot into recovery by pressing vol up/vol down to navigate between the options in the bootloader and pressing the power button to select recovery.
Flash Paranoid AndroidEdit
go to http://paranoidandroid.co:8000/roms/maguro/ and download the latest rom. Optionally, go to http://paranoidandroid.co:8000/gapps/ to download the google apps package. The google apps package will give you access to google play services, as well as other google services such as calendar or youtube.
There are four types of gapps packages. Full, stock, mini, and micro. Full and stock provides most of the google apps, and are the recommended packages. However, if you wish to have a minimal install or want to install the google apps manually, you may wish to choose the mini or micro packages.
once you've downloaded the zip files, type
adb push \path\to\rom\zip /sdcard/
and if you want to install Gapps, also type
adb push \path\to\gapps\zip /sdcard/
Now, in twrp, touch on the install button
choose to install the paranoid android rom file, and then swipe when promted to flash the zip file.
Once this is done, you will do the same with the gapps zip file if you want Gapps to be installed.
press home in TWRP, and then choose reboot -> system. Installation is complete, and now you have a Galaxy Nexus running paranoid android!