Hi,
in dietpi-config i found: Custom script (background, no autologin) and Custom script (foreground, with autologin). Can you explain me what is and the difference?
Thank you
FS
With the first option, the script is executed at boot, but you need to manually log in (like in option 0) and you will not see any possible output of the script in the terminal, since it’s started in the background.
With the second option, the script is executed as the user you chose (make sure this user can execute the script, which is located in /var/lib/dietpi/dietpi-autostart/custom.sh) and you’re automatically logged in as this user and you will see output from the script, if there is any.
nope, should be executed in background like a service. No user login will be executed or is required.
Yes, what I was trying to say is, that you want to login in, you have to do it manually. Despite the fact if you login or not, the script will be executed 
Maybe this blog post may serve as a very easy example how the user scripts in dietpi.txt may be used: Install a DietPi desktop system in a few steps.