I have just gotten my travel visa (B2) to USA for 10 years. I am going for my graduation and then traveling for four months. Afterwards I'll be traveling South America for five or six months.
Is there a certain amount of time that you are allowed to stay in the USA at one time and how do do I go about booking my return flights? Will they still allow me in the USA if my return flight is a year later?
You can arrive to the US as many times as you wish within the ten years but the actual entry grant will be given by the CBP officer. After a few questions, the officer will stamp your passport with an amount of time (usually 6 months). This determines how long you can stay in the US during this time. Should you leave the US, that stamp duration is automatically ended and you can go anywhere for as long as you want and come back to the US and get stamped again. Of course, as long as it is within the 10 year period of the visa.
Just remember that having the visa is not a guarantee of being allowed entry. It hardly ever happens but technically a CBP officer can deny you entry.