I just installed this by myself.  It’s a little bit of juggling but I doubt there is enough room for 2 people to maneuver around the average toilet.  
I installed this in my auxiliary bathroom for guests and myself.  
Important to get the connections tight, use the tape it helps a lot.  
The instructions are not so straight forward though.  The clear rubber baskets set into the grooves on the back of the unit and the round adjustment panels sit inside the round holes on the front of the unit.  
4 stars because well, it’s not a fully function8ng heated seat and water with massage function, but it’s easy, simple and economical for a guest bath.