On the lake (and I suspect in many places in Italy), you have to purchase your bus ticket before you get on. They are usually sold in a bar or shop near the bus stop. This can be most annoying if it is a shop as they are generally shut between 12.30 and 3.30. So you have to be prepared in advance.
On the word Fermata. It comes from the verb fermare (to stop). You can fermare a bus but if the bus is stopping then it is fermarsi (a reflexive verb - one where the action is being done by the bus itself). La corriera si ferma in Piazza Cavour (The bus stops in Piazza Cavour).