Watch the C Major Chord Inversions online guitar lesson by Frank Vignola from Inversion Excursion

Let us start with major chord triads in C major. All "fancy" chords start with a triad. The major chord triad is C-E-G which is the first, third and fifth step of the scale. This is the basis of all major and dominant chords. We start with the triad on the 1st, 2nd and 3rd strings. Root position means that the root or C note is in the lowest part of the chord or in the bass. First inversion means that the 3rd is in the bass and the 2nd inversion means the 5th is in the bass. Same chord, but different way of putting notes together.
In this section we go through the C triad on all the different sets of strings. 1st, 2nd and 3rd, then 2nd, 3rd and 4th, then 3rd, 4th and 5th then 4th, 5th and 6th. We also go through what I call the spread inversions where a string is skipped to give a larger sounding chord. Then we move onto the extensions such as major 7th, major 6th and just about every other chord extension I could come up with.
Don't forget that learning your triads will help you to learn the extended chords because all extended chords are based on the triad.