1. Rhythmic patterns are groupings of long and short sounds in a given meter, with mastery of beat, meter, measure, and bar lines being important for constructing and performing rhythmic patterns.
2. Time signatures indicate the number of beats in a measure and which note receives one beat, guiding musicians in correct rhythm and timing. Simple time signatures have 2, 3, or 4 beats per measure while compound signatures like 6/8 double the time value of notes and rests.
3. The document discusses simple and compound time signatures, provides rhythmic pattern examples for different signatures, and includes assessment and enrichment activities to solidify understanding of constructing rhythms based on time signatures.