Can you outline the steps you took and your starting point? TIA
Its pretty much a straightforward process after unlocking the bootloader..
download this one on your PC
Global A13 Beta2
Edit: Also dont forget to backup files since this will wipe all your data
1.Extract the downloaded file using 7zip/Winrar until you get a folder
2.Connect your phone in fastboot mode
3.Open the extracted folder and click the flash_all.bat
4.Wait for it to finish
5.Done
For rooting
1.Download the latest magisk apk
2.From the fastboot rom folder, grab the boot.img and transfer it to your phone with the apk you have just downloaded
3.Install the magisk on your phone and patch the boot.img
4.Transfer the patched boot.img to your pc and flash through fastboot
5.Reboot and install any modules you want