Sometimes it can happen that nothing works at all on a smartphone like the Huawei P20 Lite. Then the time has come to perform a so-called soft reset.
This is a process that causes a restart. This is always necessary when the smartphone no longer reacts, neither to inputs via the screen nor via the buttons:
This is how the restart or soft reset is performed on the Huawei P20 Lite
Press and hold the following button for about 15 seconds:
Power On/ Off Button
Then the Huawei P20 Lite will restart itself from now on and boot the Android system. You should now be able to use the Huawei P20 Lite as usual.