Need help quick. How much and how often to feed?

I've decided to start supplement feeding one of the kittens. Its just not gaining any weight and is starting to get skinny. The other two keep kicking it away from the nipples. I checked its mouth for a cleft palate or any jaw deformities, but everything seems good.
I have some KMR here, but the only problem is I don't know how much or how often to feed it. I'm going to use a small 1cc syringe since that's all I have on hand (not to mention the kit doesn't seem to be suckling well, so a syringe might be easier)
I know I should feed it right after its tried nursing from the mother, but do I feed it a certain amount, or just feed it until it stops? Also, since its still in with the mother, do I need to stimulate it or will she do it?
I'm sorry, but I have no idea what I'm doing.

Here's what I found from a website on How to Feed Kittens.

"The kitten should receive about 8 ccs of formula per ounce of body weight per day. The kitten will need to be fed about every 2-3 hours, if under three weeks old. This includes in the middle of the night. By the time the kitten is three weeks old, the feedings can be decreased to every six to eight hours."