Making Multiple Loop Cuts

I have a cylinder that I want to make many loop cuts in so I can reshape it. (Loops cuts are around the perimeter, i.e. rings)

I’m using Blender 2.8.

Every tutorial tells me I can add a loop cut, press Ctrl-R or PgUp/PgDn and this will allow me to multiply the number of cuts.

This does not work for me. When I press Ctrl-R the cursor changes to two short black arrows – when I slide the wheel, the one ring slides up and down the length of the cylinder. (PgUp/PgDn does nothing at all.) Haven’t found any combination of keys that will allow me to multiply the loops.

(I guess, failing anything else, I can always add additional cuts manually.)