Help! Newbie Diesel owner here.

[GSK11740]

Hi. My first post here. I just bought a '79 300SD for a fix-up project. Body and interior is in fairly good shape. Problem is this thing hasn't run in about 12 years. Supposedly the injector pump was bad and there was one in the trunk but nobody knows if it has already been swapped out or not. I've worked on and restored a lot of cars but I know absolutely NOTHING about diesels except for the basic theory of how they work. I have never worked on one. Where do I start?

Thanks!