Many of my songs start with 8 bars of intro, I get settled, I check the exits, the fire extinguishers, and the woman serving drinks after I press play.

So bar one, (if the key is F)

F.d (means only drums)

Bar four

F.db (means drums and bass) (sometimes I use f5 and bring the bass in low.

of course

F.p is piano only or Bb.p or whatever your chord.

The other way us to highlight the bar you want to change and use f5.

Sometimes I go wild and shove in the bass chord as in

F.b (look ma no drums, no piano, no strings, no soloist, just a bass solo. Just remember to quit it before everyone leaves.

Those dots or periods have other great meanings, and I'm sure these will be revealed to you in subsequent attempts to seek the light, as you head east.

John Conley
Musica est vita