Grade is the contrast between black and white, think like the grade of a hill. Steep is contrasty (5) Gentle slope is flat (1). Grade 2 or 3 is normal. With variable contrast you can use purple (5) to yellow (1) filters to get any number in-between.

Probably won't matter to you because you just want to get results. The grades are usually used to refine the look.

A respected subscriber here, Ralph Lambrecht wrote a book which we all love called "Way Beyond Monochrome" - On his website he has sample chapters, including one for how to poke a pinhole. Basically start with a ballpoint pen to dent... then follow-up with a pin to make the hole.