I have just bought a 4 days consecutive swiss pass for me and my family. We will be travelling from Milan to Interlaken. As I have understood, we only need to buy ticket from Milan to Domodossola and rest of the leg till Interlaken will be covered on swiss pass. My question is, how to do that? Shall I only search for Milan to Domodossola on SBB and buy that ticket? Or is there a system in place in which I can specify that I have a swiss pass and it can take care of the rest?
Also, how can I make the reservation for Milan to Interlaken?