According to the wiki the grit rating are as follows:
Green
5-8 micron, very aggressive
Black
1-3 micron, medium
Yellow
a strop conditioner for leather conditioner only;
the sequence would be: green followed by the black. The green is rated as a rather coarse so I would be very careful with it. The yellow should be reserved for if/when your strop dries up and need some conditioning.
Here is a good thread on the topic and another useful thread here on applying the stuff. FWIW, I like to have one strop with no paste for general use. Paste all the time is too much of a good thing IMO.