Geneva is an easy city to get around. It is small, so you can walk everywhere and there are numerous bridges that cross the lake.
There are small taxi-boats that cross the lake regularly (called Mouettes), and trams and buses that can take you up the hill to the old city if you’d prefer not to walk.
The use of the boats, trams and buses are free. Your hotel will give you a travel pass which lasts as long as your stay in the city.