1.Run "Install drivers"
2.Turn off phone,pull out battery,and insert it again after 5sec
3.Hold volume DOWN and turn on phone while holding it
4.If you want,run "Check Bootloader Status" in HuaweiY300 AIO App to check if is it locked or not
5.Turn off phone. Press and hold Vol DOWN and Power buttons to enter fastboot mode
6.Press "Volume down", "Volume up" and "Power" buttons. Hold them pressed for 5 seconds. Phone screen should become purple/pink. Connect phone to computer using USB cable
7.Run "Bootloader Code"
8.Detect device by selecting Huawei phones from manufacturers drop down menu list, then click magnifying glass button
9.You will find Bootloader code in text below
10.Disconnect usb
11.Turn off phone. Press and hold Vol DOWN and Power buttons to enter fastboot mode
12.Run "Unlock bootloader" and enter code you got from "Bootloader Code"
13.The phone will execute some checks, restore factory settings and finally reboot,after that disconnect usb
14.Turn off phone,pull out battery,and insert it again after 5sec
15.Hold volume DOWN and turn on phone while holding it,and connect usb
16.Run "Install Recovery" and follow instructions
17.When the recovery has been flashed successfully, your phone will reboot
18.Run "SuperSU(root)" and copy file to your memory card
19.Disconnect USB
20.Turn of your phone. Hold the Volume UP and Power button simultaneously until the TWRP recovery menu is displayed.
21.In the TWRP menu choose “Install” and navigate to ”SuperSU-v1.86.zip” in the root of your SD card.  Once the installation has finished choose “Reboot system” to reboot your phone.

Unlocking Bootloader,instaling TWRP and Rooting is now DONE!!!

To Flash Cyanogenmod:
1.Copy Cyanogenmod zip file from modaco
2.Copy Gapps
3.Turn of your phone. Hold the Volume UP and Power button simultaneously until the TWRP recovery menu is displayed.
4.Wipe data/cache(factory reset)
5.Install Cyanogenmod zip
6.Install gapps
7.Choose reboot,wait....and enjoy

-------BY ProHunter----------