hello...
personal preferences. here..
change oil and filter.
first of all make sure the motor will turn freely by hand.
would suggest removing spark plugs and adding a little oil to the cylinders to maintain compression and minimise starting damage.
when electrics are ok ... leave the plugs out and turn it over on the starter motor to get oil pumping around the block, (at least 30 seconds)
when all turns freely and there is fuel in the carburettor...
assuming the timing is acceptable, replace the plugs and try to start it.
if it starts, listen carefully for any sounds of really dodgy running and shut it down immediately if so.
let it run for a few mnutes and make sure the coolant is being pumped through the radiator as the thermostat may be seized.
check the generator / alternator output at the battery terminals, should be around 13.5VDC
be wary of exhaust damage as exhaust fumes may not be vented properly.
best of luck with it.... hopes it runs well...