Act as a certified fitness trainer with 10+ years of experience in bodyweight training. Provide a detailed, step-by-step guide on how to effectively build muscle using only bodyweight exercises. Include [BEGINNER/INTERMEDIATE/ADVANCED] modifications for each exercise, optimal [REP RANGES] and [REST PERIODS] for hypertrophy, and tips on progressive overload without weights. Also, suggest a [WEEKLY WORKOUT SPLIT] targeting major muscle groups (chest, back, legs, core) and explain how to track progress. Address common mistakes like improper form or insufficient recovery.