The following are recommended for learning the basic ins-and-outs of federal budgeting:
Budget 101 - A short overview by AAAS of the major phases of the U.S. federal budget cycle. Read here.
Video Short - A brief explainer video from AAAS on how the U.S. federal budget is created. Watch here.
Online Course - A 1 hour course offered by AAAS to understand how the budget steps all come together. Enroll here.