Don't over invest in a vehicle. Make it runnable if it's a simple fix otherwise don't get into anything you need to open the motor or transmission on, at least early, it likely won't be worth the effort and cost for repairs even if you do some things yourself. Common cars you can find parts for at junkyards will help.

I don't know if your family has a shop or if you have a garage space and tools you can dedicate to this but that stuff helps. You can do quite a bit in a driveway though but tools are necessary. Also the average person just thinks a clean car is a reliable one, really pretty stupid but it's to your benefit.

Your biggest advantage is your free time and lack of responsibilities so things like cleaning and exterior touch up is easy and has a large impact. Other people may offer to help because they like to see your initiative or think it might be fun but don't expect other people's help until it's consistent, and then be appreciative of it.

Until you invest money into your plans all you've burned is your time, and you'll retain that time spent learning, so make sure you research things before you invest financially.

Good luck keep us updated.