I would start by draining the oil and replacing the filter, and refilling the crankcase with a good quality oil. You will have to replace the fuel, and cross your fingers and hope that the old fuel has not varnished the system. If the system was varnished (a thick insoluble film) you will have to remove and either replace, or thoroughly clean the varnish from any part that is gummed up with it. Once this is done, either charge and test the battery, or install a new one. Then you can try and start the vehicle, and move on from there. a repair manual will help you with alot of these tasks. Find a mentor or friend that knows about cars and learn from them, and mostly have fun, cause its not easy to make money in the restoration business, so you might as well enjoy it as a hobby, that way you get something out of it.

First thing is to do is determine the ownership of the car. Secure the title in your name. As for the ignition keys take a door panel off and take door lock off. Take that to a GM dearlership or good locksmith to key the ignition lock there should be a number on this lock.to aid them.
There is a good chance the carb has gunk in the bowl a rebuild maybe in order before starting or at least an inspection of the carb as to the condition of it.
As for the fluids check the water in the radiator Change the motor oil
Before you start the car don’t worry about the transmission oil till you have the car running. a new battery is in order a look under the dashboard to see if mice damaged any wiring this could cuase a fire if they short out once you are sure all these things are good twist the key. dribble a little gas into the carb to aid in start-up
on more thing join a yahoo group pertaining to this model of car for future help on questions pertaining to the car.
Hilo

replace all fluids; oil, gas, transmission fluid, brake fluid, washer fluid, radiator fluid, any others you can do. Since there were rats in it i would suggest rewiring the car so you don’t get a short somewhere where the rats ate through a wire and set the whole car on fire and the interior probably needs reupholstered. Since it’s been sitting so long it will need new tires and battery guaranteed, the rest i would just have to see for myself but this should help you. You can also sell the car, i don’t know what kind it is but if it only has 45,000 miles on it you could probably get a lot out of it

Fresh fluids including fuel. Fresh tune up, air filter, fuel filter, your shouldn’t have any problems at this point. If you do what I suggest.

tough really so you would have to know what and how to work on a car to start by reading a few books so get a repair manual on that car wil help you then by typing thing like how to restore old car how to start old car might help with some of it as well most likey wil need a repair manual to look at while doing it but you can find most car repair by typing what you wish to replace like how to repalce starter how to repalce brake pads many videos as well find same way how to replace brake pads video but get a repair manual for sure and yes fuel system wil have to be clean old fuel drained and have to know why it was park to repair that lot of work a head of you

I’ll give you $100 for it.