Install CyanogenMod 10.1 on Nexus S (crespo)

Hi !
Today I'm back for an article about Android. My Nexus S is certainly old, but not dead !
This is the step to install the new CyanogenMod 10.1 (Jelly Bean 4.2.2) on your device.

Prerequisite

1) Android-sdk

you need adb, and fastboot to unlock your device and push the CyanogenMod package. you can download it here. You may need to start eclispe and install plateform-tools to get adb and fastboot.

2) download 

your the update packages from CyanogenMod. you will need three packages.
the first is recovery menu ClockworkMod (direct), the second Android Cyanogen, the third is the Google Apps (Play, Maps, Agenda...)

Install

Once you got everything, start a shell or powershell and go to the platform-tools in android-sdk

1) rebooting the device in bootload mode

adb reboot bootloader

2) We will unlock the device :

fastboot oem unlock

3) flashing the new bootloader ClockworkMod

fastboot flash recovery your_recovery_image.img

4) installing the new ROM CyanogenMod

In the menu select install zip from sideload

adb sideload /path/to/cm-X.y.z-crespo.zip

Go back

5) installing the Gapps (Maps, Play, Agenda...)

In the menu select install zip from sideload

adb sideload /path/to/gapps-jb-YYYYMMDD-signed.zip

6) Reboot

Go back and select reboot system now

7) Enjoy your new device

Tips & Tricks :

Enable developper mode :

- Go to Settings > About Phone

- Find the entry "Build number" (on the bottom of the list)

- Tap 7 time on it