tbh it really depends on how long its been sat and how lucky you are, it's gonna be step by step to check what state things are in before moving on.
Full fluid change (coolant, engine, oil, gearbox, diff etc etc), fuel in the tank will need draining and replacing, fuel pump in the tank, fuel filter in the engine bay, all belts, tyres (as im assuming multiple years) all filters, prob spark plugs as well.
I would sugest first making sure you can hand crank the engine so you know its not siezed, Prob then worth doing the engine oil and filter, collant, fuel and fuel filter then see if you can get oil pressure before then trying to fire it up. If you cant get it started could mean there are more serious issues at which point your then into is it worth pulling the engine etc etc. A bad example could be if it was stored without proper coolant and just had water in it. If so it could well have frozen and split the heater matrix, lifted the head etc etc Additionaly a leakdown test would be a good idea.
!!!!!!!!!Make sure you crank the engine over without letting it start to get a good flow and good pressure before trying to start it!!!!!!!.
After that its prob a case of seeing what happens, you may find lots of dfferent fluid leaks (be very carefull of anything that might catch fire!!!!!!!!!!!!!) from withered pipes, failed rubber seals etc etc, all you can really do its see how it goes.
If you get to the stage of test driving it, be very carfull of failing brakes and leaking suspension when you drive it. i'd advise very gradual steps.