Getting baby on a schedule

How do I get my baby on a somewhat schedule? He just turned 4 months old. Also how do I get him to fall asleep on his own? I can't give him a bath every night because I have back problems and need his dad's assistance. Most nights dad falls asleep on couch. I really wanna get my baby on a better night time routine and a somewhat schedule. During day naps are only 20-30 minutes... So I'm lucky to get a quick shower. Any advice would be greatly appreciated! Also I heard of a book 12 hours of sleep by 12 weeks. Is it any good? Should I try it even though he's already 4 months?