I am new to the forum but have been 3D printing for a while now. As someone who started 3D printing on an Ender and still has one as one of my printers, I can assure you it will not need to be totally rebuilt to work. One thing it will need to be though is tuned, No printer is truly plug and play and all will need some tuning to perform at their best. There are lots of videos on Youtube that will help you with getting this done. I have learned a lot from Makers, Muse, Teaching Tech, The 3D Printing Nerd, and Dr. Vax on there. I would suggest that as the place to start. Once tuned then you can start working on getting some great prints. As you progress I guarantee you will want to mod your Ender 3. First thing I did was get better springs for the bed, the factory ones are terrible. There is a large amount of mods available and a huge user base that will be willing to assist you on forums, Facebook user groups, Youtube, Reddit, etc etc. TomB19 is correct that one of the best ways to learn is by doing lots of research and lots of printing. Print, and print, then print some more. I would suggest using a good quality filament. My go to for PLA is Hatchbox and I have had very good luck with it. curious aardvark hit the nail on the head about PETG. It offers strong parts but it can be a pain to print with. It really likes to warp while printing. I have found the best way to print this is with your printer in an enclosure. Nice warm environment and absolutely no drafts is the key to success with PETG. Best of luck on getting going with 3D printing. Starting out can be extremely frustrating. It sure was for me. But don't give up, it will be worth it, believe me. Get printing and reach out for help when you need it. Before you know it you will be a Michelangelo of plastic.