Most of the sheet music you will buy will be arranged for piano. Piano music is written using two or three staves, with the chord symbols written above the top staff. It may also contain unfamiliar symbols and terms. At this stage you need only look at the top staff, which contains the melody line (tune), the lyrics and the chords. In some sheet music chord diagrams may also be included. As most sheet music is arranged by keyboard players quite often the guitar chord shapes given are incorrect, unnecessary or impractical, and many piano arrangements of guitar based songs do not sound anything like the recorded version. Guitar tablature versions of sheet music are gradually becoming more popular and in many cases are very accurate arrangements of the song.
Also, many piano arrangements are in difficult keys for a beginning guitarists and quite often use unnecessary chords. Piano sheet music also gives no indication of how to strum the chords. So piano sheet music is only a guide for a guitarist but is useful for lyrics and a general chord guide.