This lesson is to learn what are the notes that compose each different chord. This is not a lesson on playing chords on the bass. A chord is basically just several notes, played at the same time. For example: C Major is C, E and G played simultaneously. Mastery of chord structure is necessary to be able to play the right notes while you create bass lines over each chord change.
Inversions
Unless you are composing in a particular classical style like Baroque, where some rules apply, the order in which you harmonize the notes together is up to your own musical taste. For C Major, you could be playing E, G and C, or G, C and E, or even C, G and E. Or you may double any of the notes like C, E, G and C again or C, E, G, C, G, etc. The choice is yours. You may want the melody note on the top. Also, some instruments sound better than others with certain inversions. Finally, you don't have to play all the notes of the chord. For C Major, you could play C (the root) and E (the third) or C and G (the fifth).
It definitely depends on the effect that you want to create, or on the style of the composition. All this comes in very handy for the bass, because due to its low register, it is better to play only a few notes of the chord with big intervals. For example: C on the 8th fret of the E string, and E on the 9th fret of the G string (one octave up or a 10th) sounds very good for a C Major or C Major 7th. In order to create a good bass line, it is necessary to know the exact composition of each chord.
Intervals
A chord is made up of different intervals. The basic intervals follow the 2 octaves of the major scale. For C Major: C is the Root or Tonic. D is the Second, E is the Third, F is the Fourth, G is the Fifth, A is the Sixth, B is the Major Seventh, C is the Octave, or Tonic, D is the Ninth, E is the Tenth (or third), F is the Eleventh (or fourth), G is the Fifth, A is the Thirteenth (or sixth), B is the Major Seventh.
If you alter any of these notes: Db is the Flat Ninth, D# is the Sharp Ninth, Eb is the Minor Third, F# is the Sharp Fourth or Sharp Eleventh, Gb is the Flat Five, G# is the Sharp Five, Ab is the Flat Six or Flat Thirteen, Bb is the Dominant Seventh or Seventh.
Learn each individual chord looking at the intervals to be able to play them starting from any root.