The federal budget process occurs in two stages: appropriations and authorizations.
Stage 1) a budget bill, which provides a framework with guidelines outlines a sense of direction and programs to be supported with a final funding authorization. Budgets are typically made for single fiscal year (October 1 through September 30 of the next year).
Stage 2) an authorization bill, which directs how federal funds should or should not be used. (It does not set overall spending limits, however, which are the subject of appropriations bills.) Authorizations are typically made for single fiscal years (October 1 through September 30 of the next year) but are often renewed in subsequent law.