How to use the electric shaver? Why does the first shave hurt a little, and it can't be washed clean …

This is normal ... if you don't shave, then your beard is very soft. The blade of electric shaver is protected by net cover inside and outside, so you can't directly touch the skin. Plus, your beard is so soft that you can't shave it clean. Scrape hard if you can't clean it, which will be very painful. These questions are normal, just get used to them.