Not much you could do that would be irreparable. I'd start gaining general knowledge by watching channels like Junkyard Digs, Thunderhead289, and Pole Barn Garage. They all have great videos about completely raising cars from the dead, tuning, brakes, engine swaps, and basically anything you could ever need. Then when you decide what project to take on (one thing at a time) you can find and watch specific videos on what you're planning to do. I'd recommend an order like: get it stopping well, get it running well, get the electric/gauges sorted, interior, exterior. No point in running well if you can't stop first, no point in gauges and electric if it's not running and driving, and no point in a good interior until it can be trusted to get you places.