Right the piano charts on this site can be difficult sometimes. The LH is a good place to start, but not always the best note to play. It is also good to look at the RH which will be playing the chord (or some inversion of it). The LH usually plays a single note (but not always the root!). Let's look at an example. Since you know some theory this should make sense. If anything is unclear just ask!
Here is the start of a song I pulled from here:
http://www.learngospelmusic.com/forums/index.php/topic,27555.0.htmlEb / Eb-G-Bb Go- <--- Here the LH is playing the root. Notice RH has an Eb major (Eb root, G third, and Bb fifth).
F / Db-F-Ab od <--- Here the LH has a chord tone (the third), but not the root. Notice the RH has a Db major chord.
G / Eb-G-Bb of <--- Here the LH again does not play the root. Notice the RH again has our Eb major chord.
Ab / Eb-Ab-C mercy, <--- Here the LH has the root! Notice the RH has an
inversion of an Ab major (Eb fifth, Ab root, and C third)
Db / F-Ab-Db God of <--- Here the LH has the root. Notice the RH has an
inversion of an Db major.
Playing the piano LH notes on this song shouldn't sound "wrong" because in each case the LH has a chord tone, but it is good to know the root note. The root note is almost always the best note for the bass to hit (especially if the chords are changing fast and you only have time to hit one note).
You probably picked this up, but an inversion is just the with notes "out of order". For example:
C major: C-E-G
1st Inversion: E-G-C
2nd Inversion: G-E-C
For more info on inversions:
http://en.wikipedia.org/wiki/Inversion_(music)It is good the recognize inversions because it will help you find the root note.
Hope this helps!