@Substring How do I type with no video? Should I do this blindly? I use CRT most of the times for a real retro experience. I do not own a HDMI monitor/TV.
The Wiki does not tell me how to do what I need, i.e., automatic switch (as Retropie does by default).

@Substring Thanks. The wiki is not clear on what to do to have a Recalbox that automatically switches!to the used video as Retropie does without any tinkering. I hope they will soon make such a setting the default one. What do I need to edit the file without any video output? What should I use on a PC?

@voljega What is the effect of this complicated procedure?
https://github.com/recalbox/recalbox-os/wiki/Connectez-votre-recalbox-à-un-CRT-avec-composite--(FR)

Will Recalbox use composite when plugged to composite and HDMI when plugged to HDMI?

@Substring Sorry for not being clear. I would like to try Recalbox but my first experience is negative due to the fact that I am getting no video. By "both" I mean that I want to use Recalbox on different TV types but NOT at the same time. How can I do this?
So far I have only used Retropie and it worked straight away by selecting the correct video output depending on the used TV .

@voljega
It looks like Recalbox by default makes things complicated for no reason.
How am I supposed to edit a file if I have no video output?
Is there a simple step by step manual?
Retropie requires no editing of config files to get something working.

@Substring
No video at all. It looks like Recalbox requires you to edit some config file.
I wonder why they made it complicated.
I would like to have a Recalbox that produces a video output on both HDMI and composite depending on whatever it is plugged in.

Recalbox 4.0.1 produces no video on my Rpi2 when connected to my CRT (Retropie works fine out of the box on both HDMI and composite).
What sort of settings do I need to do to have Recalbox 4.0.1 work?
I thought it was at least as simple as Retropie but I now have the impression that I need to do some manual settings.