changing hydraulic fluid on a 1066?

Hi, I need to change the hydraulic fluid on my IH 1066 and realized I have absolutely no idea where to first, drain the old fluid from and second, where to add the new stuff. I have uploaded a picture that shows where it seems like it should be drained and added but I really have no idea. There seems to be only one receptacle for adding fluid on the tractor that I can find the capped dipstick in the top middle of the picture and would the reservoir beneath it, bottom middle in pic, also be where to drain it? There is also another tank or reservoir beside the one picture, but nowhere to add anything that I can find. Both bottom tanks have bolts in the bottoms, I assume that are just loosened and the fluid drains out? As you can tell I am not particularly handy with this job but it needs to be done so if someone could run an expert eye over the situation and give me a few tips that would be great. Thanks very much. John