Get out your parts books and start studying them. The carb is one of the simplest in the business.
How old are you again? We also need to have a little dialog about tools and a work environment before coaching you on tearing into your new bike. There are certain tools and supplies you MUST have on hand. I know it is tough to think about spending money on this stuff right now, but we need to get you set up first. No Toil and air filters, tranny oil, good quality tools, a tube of anti-seize, blue loc tite, waterproof grease, dialectric grease, torque wrench, etc. All these things will aid you and us in getting you up to speed.
Your pop knowing how to do a needle but not a main gives me a pretty good idea on his abilities.
Break-in has been covered here and in the KDX forum at nauseum, so you may want to do some searches on that subject.