The tools are from YouLinw233 on Weibo.
Download the tools:
Download Magisk, Magisk Manager and Open GApps (ARM64, Android 8.1, I got an error when trying to flash the full package so get the stock one), install Magisk Manager and copy everything else on your phone.
Enable "OEM unlocking" and "USB debugging", connect the phone to your PC and run glass.bat, you should see a menu.
First press 1 to install the drivers, then press 2. The phone will reboot in fastboot mode and flash the recovery.
Now on your phone select "Reboot into recovery mode" with the volume buttons and press the power button to confirm.
TWRP should boot, from here you can flash Magisk and GApps.
If pressing 2 doesn't work try to unplug your phone, boot it in fastboot mode by pressing volume down while it turns on, connect it again and press 3 on the menu.