On the guitar, the right hand patterns are basically 
simulations of a samba ensemble rhythmic section. 
Notice that the syncopation is usually down with the 
right hand fingers 1, 2 and 3 (playing the top voices of 
the chord), while the bass note (played with the right 
hand thumb), comes on the beat.

The bass line keeps switching between the root and 
the fifth of the chord, and it's a better choice to play 
the fifth below the root. If the bass note is already 
placed on the 6th string, you may keep the same note 
for the whole measure.

You can practice these patterns and variations the 
string with your left hand. Try using "6/9" and "m9" 
chords, II -- V progressions or turnarounds.

It's also a good idea to practice away from the guitar, 
clapping hads on the high vouces and tapping the low 
voices with your foot.

Musical example (Figure 2) applies the basic samba 
pattern to a typical samba progression