I don’t have Fibaro roller blind Relay, but as far as I know, the Fibaro ones support all kind of buttons, switches. I think it has two switch inputs.
It can be Momentary (press and release or hold) or Permanent/Toggle switch (interlocking).
It might support single Momentary switch too.
The most common way is the interlocking physical switch. Where you have got two switches, what are inter locked and self locking (Only one can be on at the time.) Up and Down switch.
When you press down it starts moving down. Depends on settings Momentary or Permanent, if you toggle down back it stops (Momentary) or keeps going down (Permanent), in this case you need to press the down button to stop it. It does work the same way for up.
Or there is the option when the switch is itching and inter locked.
Or have a single switch, itching, and that repeats down stop up stop commands.
It would definitely not work with a 3 button switch it has only 2 input.