To get into Florence the city, from the airport for Florence (FLR), you can get the very easy tram, or a taxi.
Both will take you to the Santa Maria Novella railway station in the centre of Florence.
Then you can get a train from there to wherever you need to go.
It would help to know if you are wanting to go to Lake Como, which is very big and has many towns and villages around it, and if so which town on the lake; or the actual town of Como itself.
If, as someone else thought, you are joining a RS Tour in Varenna, you would be better flying into Milan Malpensa.
Both your posts suggest that you are not quite sure where you intend to get to, so we just need a wee bit more detail in order to help you out.