Tomorrow I a travelling from Erfurt-FRA in J on a LH train segment before my flight in F from FRA-IAD. I am totally unfamiliar with the process. Do I just sit on the train and show them my ticket on my phone? Where is my luggage collected? Can I keep a duffel bag with me (I have some fragile things in it)? Will I need to pick iup all my luggage at the train station in FRA and bring it myself to the first class terminal? THANKS!!