Brush up on what ad man Don Draper and the ad folks at Sterling Cooper Draper Pryce have been up to as the AMC show returns Sunday after 17-month hiatus. By Josh Wigler Jon Hamm in “Mad Men” Photo: AMC “Mad Men,” like the advertising world it revolves around, is a busy show. Lots of comings, lots of goings, lots of inside baseball, lots of Jon Hamm getting drunk. Making matters even more complicated is the fact that the 1960s-set AMC drama has been off the air for dangerously close to two years, thanks in large part to contract disputes between the network and “Mad Men” creator Matthew Weiner. Now, “Mad Men” is finally set to return for its fifth season on Sunday night. But, as is often the case with the show, don’t expect Weiner and company to welcome you back into the world of Sterling Cooper Draper Pryce with an instruction manual. If you don’t remember what went down in the last few seasons of the Emmy Award-winning show, that burden rests entirely on you. So if you’re behind on your “Mad Men” know-how, or simply need a refresher before Sunday night, don’t sweat it: Keep reading for 10 things you need to remember about season four going into the weekend’s big season-five premiere.