It isnt hard, just do it like you would on a domestic flight. You might have to go to ticket counter to pay departure taxes though. As far a jumpseat go...
747 - 2
767 1 or 2 depending on the model 400's have 2 I believe
777 - 2
realize however that on international flight those jumpseats make be occupied by additional crewmembers thus necessitating a seat in the back. For my money the 777 is the way to go if you have to ride in the back....very comfortable, especially in business class...