I went to Menorca in October 2019 (So things will have changed following Covid).
We bought a guidebook (Kindle - so we both had access) and hired a car (so I am unable to give you any information about public transport).
There are lots of places to visit/things to do, depending upon your interests.
There are plenty of stunning coves, rock pools and beaches. Most are fairly accessible by car and parking was mostly free. The larger beaches have bars (and toilets).
We drove carefully and slowly up Monte Toro (the highest point) with incredible panoramic views of the island.
There are a number of pre-historic sites on the island and we visited two (which the guidebook provided us with information on).
I would highly recommend the quarry at Lithica (it was the unexpected highlight of my holiday).
Parking was difficult at the port in Ciutadella but we enjoyed our guidebook walking tour. We went on a short boat trip here and there are plenty of places to eat out. Mahon also has a great harbour, restaurants and bars. We were AI (and the hotel made first class picnics) so we did not eat out - although we had a few drinks!
Other trips we made include a massive fort - Fortress of Isabel II, a boat trip around the island and Cova d'en Xoroi (caves/night club) to watch the sunset.
We really enjoyed our time and I hope you have a good holiday too!