International is much like CONUS just that you have to fill out each line separately (ie. Name, Street, City, State, Postal Code etc), then you just have to fill out whats in the package and declare the value. Print it out cut it and take it on the package and you're good to go, no additional work. All they do at the post office after is just scan it, if you don't have time to wait for them to scan everything, look for a post office near you willing to take in mass shipments and you can just drop it all off and be on your way.
You can fit 2 labels one 1 piece of lettered size paper also be careful when you print international and CONUS, international prints on the bottom of the paper and CONUS prints on the top of the paper, you need to keep this in mind when you're trying to fit 2 labels on 1 piece of paper