triplets are one note play three times in quick succession 
they are usually played with the index middle and ring fingers 
a good example is the song the toys go winding down

G——————————101010—111111———————————————————I
D——888—888———————————————888—888—11—888————I
A——————————————————————————————————————————I
E——————————————————————————————————————————I

G———————10*—11*——————————————————I
D——8*—8*————————8*—8*—11*—8*—————I
A————————————————————————————————I
E————————————————————————————————I

* — triplets 

those are the two common ways of notating triplets 

triplets can alow you to play faster or add more notes in to add 
ornamentation

triplets are icing on the cake in any song to put emphasis an any 
note

keep practicing