Maybe you should tell us on which System (Raspberry Pi (which on ?), PC, Odroid or something else) you're running Recalbox.
It's not personally, but it seem that most People who are looking for Help here on this Board don't know the Recalbox-Wiki.
Most of their Question can be answered there.
So just look here
https://wiki.recalbox.com/en/basic-usage/features/boot-videos