OBS on Linux: Green screen and virtual camera for video conferencing

OBS Studio: My monkey enjoys the beach

Similar to many of you, part of my work and hobbies consists of video conferencing. For some time now, I have been using OBS Studio (Open Broadcaster Software) to create a virtual camera on my Linux system. Recently, I had to upgrade my kernel. It required to recompile some file and reminded me that I wanted to blog about it. As usual, this is how I remember all the interesting stuff. So what is needed to create a virtual camera with OBS Studio and can you use a green screen for some beach feeling like shown?