Several websites offer instructional material that begins with the basics and moves onto more complex studies (see Resources). Before you pursue the more complex lessons, start with instruction that teaches the parts of the guitar, how to change strings and how to tune. Many beginners pay a music store to change the strings on their instrument, believing there is some trick to it. The process is simple and needs to be done regularly, so learning to do it right away is an important beginner's lesson.
Chords are fundamental to guitar players. Learning just a couple of basic chords will give you the information you need to strum along to hundreds of songs. A beginner should start with basic folk position chords and work up to playing extended and altered chords, as well as basic chords in more advanced positions. An effective approach to learning chords is to learn and memorize two or three new chords a week. Numerous websites (see Resources) teach chords and offer extensive chord dictionaries, allowing you to learn how to build and play chords without ever having to purchase even a guitar chord book.
Scales and solo playing are for more advanced players. After you've gotten familiar with the instrument, you'll want to put your efforts into pursuing more advanced playing techniques. Learning to play scales and solos will give you the foundation you need to consider playing in a band or even writing your own songs.