This may seem silly to you pros, but I am just starting out and have never used disco dust. I want to put it on the sides of the book cake I am making to look like pages. What is the best way to do this.

Certainly isn't silly when you don't know how to do something, ask
It is a very super fine dust (that some say is finely ground plastic). Just take a dry art brush, dip it in the dust, shake some off and shake the rest over the cake or items you want to dust. You can also brush it over the item if you want a more thourough
coverage.

It is "non toxic" but not considered food safe as it is ground plastic and aluminum. keep that in mind when you use it.