I did pics for this too - same idea as how you'd use them w/ the Spritzer. As w/ that you *need* re-inkers to be able to do this - just squeezing the pads together isn't going to get enough ink - the re-inkers are concentrated enough that this works *really* well and a little goes a long way!!
Dab your Blender Pen in a drop of re-inker in your choice of color (start w/your lightest color and work from that to darkest).
Color on the section of the stamp that you want in that color.
Scribble off the excess ink until the blender pen runs clear before moving on to the next color.
Using your darkest color last fill in the spots on the stamp - taking care not to run the color into the other lighter colors.
You don't need to be super-fast w/ this either. Take your time to get it the way you want it.
Huff on the stamp to re-moisten the ink and press it onto the CS.
(I used cheapo GP white CS here - it sure doesn't hold the ink as well as SU's Whisper White! I was playing around tho and didn't want to waste my SU CS!! lol)
So now you've got markers in all the new In-Colors (as well as any other color re-inker you have!). I HTH everyone!