Chords are simply combining notes together from scales. There are, again, many different approaches to how chords can be learned, but they need to be not just learned, but understood. The reason is simple—there are so many songs that have the same or similar chord progressions. Understanding how chords and their progressions work will allow students to learn a song much faster. This is associative learning, and when applied, the student is learning not just to play the guitar, but learning music itself.
Tapping is a technique where the right hand taps a string and alternates with notes played by the left hand. A basic way you can start tapping is to find three notes that you want to play on one string and play them as triplets using this sequence: tap, pull-off, pull-off. The first note is tapped with your index or middle finger and then pulls-off onto a note held by one of the left hand fingers, which is then pulled-off onto another note held by a left hand finger. Other ways to tap are to use more right hand fingers, use open strings, and to use different rhythms.
As a beginner, it is best to avoid making a pawn shop, flea market, or yard sale purchase unless you are shopping with somebody who has experience in purchasing a guitar. Having never purchased a guitar, you may not know what to look for in terms of damage or guitar quality. With that being said, a local music retail shop is your best bet. You may also shop online with a reputable company, although be sure to review the business’ return policy.