Minimal Tools and Spare Parts List?

I am trying to get back on my bike after about 6 or so years of neglect in my shed. It’s a Schwinn GTX1. I Am decent with working on things, but I know nothing about tools specific for bikes or things that are recommended to keep with you on longer rides. I have some new tires and tubes to put on due to dry rot on the existing tires. I realized I don’t have any idea how to put a bike tire/tube on either. What is the right process? What tools should be kept in a kit with the bike? What parts? (A tube or patches, etc?) What maintenance should I look into? I also have some degreaser to clean the chain and Muk-off chain lube to go on it. The brakes seem ok and most rubber appears to be in good condition, except the tires. Sorry, I know it’s a lot, but I am wanting to get back onto this bike for weight and health reasons.