@Noriko0
I've never seen this techno-miracle in my life, so yes, drawn instructions above the toilet are needed for sure
as @Marit-Anne0 and @Sarah977 said I also see "THE PROBLEM" written all over this toilet seat:)))
Hard to sanitize, buttons sprinkled with pee (in some countries man always pee in standing position), a water fountain will surprise them and sprinkle the water on the floor, etc...
Keep everything very simple + put notes/signs on everything. You will host people from all over the world and everything has to be very intuitive and easy to use or your guests will use it in the wrong way and break it. it will be stressful and costly for you to repair it all the time.
We realized we have to explain to our international guests how to operate very basic, simple, ordinary things like a door lock with a key, IKEA roller blinds, most ordinary faucets and gas stove, not to throw the diapers in the toilet, do not step on the toilet seat, etc.... it's like working in a kinder garden 😄
For example, we had adjustable dimmer with rotary knowb for the light and despite the big black arrow drawn on it guests kept pushing the knob and broke it every month at least once. We had to replaced it with an ordinary cheap and simple on/off switch.