Hello to everybody!
I’m a new member of this forum.
First of all, sorry for my scholastic English. I will try to explain my problem that is similar but not equal to yours.

I bought one way flight with Expedia from SUF (Southern Italy) to YUL (Canada) connecting to IAD (USA).
I have one only ticket number that includes 3 “steps”:
1) one national flight (SUF – FCO) sold by Lufthansa, but operated by its partner AirOne
2) one international flight (FCO – IAD) sold and operated by United Airlines
3) one domestic (I believe) (IAD – YUL) sold by United Airlines, but operated by Air Canada Jazz

Lufthansa, UA and Air Canada are all members of the Star Alliance.

I state in advance that the connection time between flight 2 and flight 3 is only 1 hour and ½ and I’ve to clear security and immigration customs (also with a child of 2 years old and my husband) .

UA (domestic and international call centre) said to me that it’s not correct that my flight in ONE, the company said that I bought a package of 3 separated flights, so I have to do more than one check-in, certainly I’ll have to recheck baggage at the Dulles Airport.

I tried to do web check-in on the UA web site (obviously it isn’t yet possible to do it, because the departure is the next December) by inserting the only ticket number that I have, just to understand the departure city and the arrival city. The result is that UA consents web check-in only for flight 2) FCO-IAD.

I require your help to understand:
- How many check-in I have to do? One, two or three! And how many boarding passes will I have?

- Am I a connecting passenger and then can I use the facility for connecting passengers at the C Concourse of the Dulles airport (I believe it saves more time, considering the restrict connection time), or have I go to the main terminal and put me on the long queues? Is 1 hour and ½ enough ?

I apologise for my, perhaps, confuse description and I thank everyone can help me. This experience is already stressing me two months before departing!