I moved to Guam from the U.S. in April of 2017. I earned income in the U.S. but did NOT earn any income in Guam. Where/how do I file and is there anything special I need?

I moved to Guam from the U.S. in April of 2017. I earned income in the U.S. but did NOT earn any income in Guam. Where/how do I file and is there anything special I need? I keep finding conflicting information but it doesn’t seem specific to my unique situation