HELP, problems with Serial.readString()

ArduinoBeginner01:
Ok, maybe its wrong to use int and i read your post about basic serial inputs but i dont understand what I could replace it with.

I don't understand.

Wrong to use int for what?

Is example 6 the wright one to use in my case?

Why not use Example 2 or 3 and send the data in human readable form? It makes debugging much easier.

...R