Most all boilers install pretty much the same, first step would be to determine where you want your stove placed, try to keep the underground pipe length as short as possible and use good pipe as it is expensive and you only want to do that part once. I typically try to place the stove where it will be easy to feed all winter without making anybody in the area aggravated by the smoke, here is the trick that I use, take a stick about 10 feet long and tie about 8 feet of flagging tape to the end of it, stick it into the ground where your stack will be and watch what the wind direction does at that point, wind directions will change dramatically near buildings and woods lines, this allows you to see what it will do at that exact point. As far as the installation we would need a lot more info about your system, are you saying that there is a transformer and switching relay on the back of the stove itself? The two circs that are on the stove would be for two different runs like one to the house and one to the garage, either one should be fine. As far as installing it, there are lots of us here that will be happy to help you but I would ask you to do it here on the forum as your questions and our answers will help someone else at the same time, be patient and good luck