Exactly what and where is the labrum,what is its fnnction.What is a slap tear and how can I rehabilitate.?

An MRI showed that I have a slap tear in the labrum and fluid in the acromium of my left shoulder and possibly a partially torn rotator cuff.I stopped lifting weights a few months ago and my symptoms have improved somewhat.I�m not really sure what or exactly where the labrum is,but I want to start to rehabilitate it,as well tendinitis in my elbows and knees,mostly the left where I had arthroscopic surgery to remove most of the meniscus and arthritis and have undergone 4 series of injections to remain active over the past 4 years or so.17 years ago I had a laminectomy and bone spur removal at L5-S1 and have chronic back and neck problems.I also suffer from fibromyalgia,which would make recovery from another surgery more difficult.My main concern right now is understanding and rehabbing my shoulders,I have rotator cuff pain in the right as well,but I would certainly welcome any advice to improve my other conditions.I can�t risk or take the time for surgery,so I�m looking for alternatives