Steps in English. Simplified and rooted in 15 minutes!
1. Download and install Fastboot ADB and Android Drivers from here. Remove all other Android drivers before you start installing this. It is better to have a clean machine without other android USB drivers getting in the way.
2. Download Intel Fastboot Tethered Temporary Recovery Session Launcher
3. Download SuperSU into your N1 device. Put it in download folder.
3a. Download pa_gapps_modular_nano from here. This is the Google Play Store.
4. Run the Intel Fastboot Tethered Temporary Recovery executable. Type ACCEPT and enter T4 option. Keep this running in the background don't close it.
5. Device will boot and go into bootloader mode. Next Go to My Computer, right mouse click and select Device Manager. Look for Unknown Android device and update driver. Important!! Select only the Android driver.
6. Once the Android drivers have been installed successfully, the recovery files will be automatically copied to the device. If doesn't happen, repeat Step 4 again.
7. Once the device is finished copying the files successfully, it will automatically boot into Recovery mode. You can install the SuperSU file from your download directory. Install google app store if you wish, but it may mess up your US AOSP keyboard. Switch to other keyboards! If you don't have it, download from Google play.
7a. Go back --> Go back --> Reboot system now --> Yes - Fix /system/xbin/su
8. Reboot the device after you have finished the installation. Download and install SuperSU.apk from the Internet.
9. Done! No more error popup messages when you run SuperSU.
It is rooted with Google Play!