Manual how to backup data from your HUAWEI P20 by USB cable
Install Drivers for your HUAWEI P20.
Install Huawei Hisuite.
Connect HUAWEI P20 to a computer by USB cable.
Turn on Huawei Hisuite.
The software should recognize your device. If not you should follow connection manual.
Tap the Back Up button, wait to read all available data from the phone.
Here you can select where you want to have your backup or live it in default directory in HiSuite directory.
Next, choose select all(to backup everything that software can from phone) or uncheck it and select what you want a backup from the phone.
If all done you got the last checkbox to select or not "encrypt with password", if you select this you must add a password to your backup and only with this password you will get possible to use it, if you forget then you can't(Use this only on a work computer or in a public place in the home much better is not use this because there is a safe backup).
Check or not like you prefer.
Press Back Up button to start a process.
Just wait until you see a Complete message, then tap the Done button.
Congratulations, everything goes well and your data has been archived.