fridge quit, where do I begin

came home last night and the fridge took a dump, all the freezer foods were melted and soupy, left it running and cleaned it out, temp inside today was 77 deg.........

where do I begin, is there some place on line , like a tutorial how to trouble shoot, I fixed the defrost term before and know A/C pretty well, but where do I begin....can you guys help me with steps to see if I can get it rolling before I have to call the pro's

its a Whirlpool ED 25 TQ side x side

p.s. the only help I can offer is my son said it was making a clicking sound here and there for about 1 week before it went

 

That clicking sound was probably the compressor going out on overload.

How old is this fridge ?

 

age is unknown we go it with the house 5 months ago, what does a basic service call cost these days ??