Repair manual

This is my first day here because I bought my first Mercedes. I found a '76 240D for $450. There is no rust anywhere and that's why I bought it. I'm more excited about this car than a brand new one. I've done mechanical work for 30 some years but I know nothing about diesels or Mercedes for that matter. I'm not afraid to tear into anything but I need guidance to do so. Please give me some recommendations for a good repair manual.