Tillers

I'm winterizing my CRT900. My question has to do with the oil filler ports and other lubrication. The owner's manual hasn't shown me much. I have two yellow and one white filler ports on my tiller. I know the front yellow is where I check and put new oil. I also know where the drain plug is. But, what is the white plug (midway up on the engine in the front) and the yellow plug for in the back? Also, what type of oil goes in the little blue cap on the tine gearbox?