The plumbing for the entire house can get a a little complicated, However for this website, I will show the basic plumbing using one heating circuit (I have two in my house, but if you have a large house, you may need more.
Basically you will have 4 connections to the boiler two for the heat exchanger and two for the in floor heating. I used 1/2 inch lines for my heat exchanger lines, and 3/4 inch lines for my in floor heat lines. However if you have a large house with a lot of area to heat, you may want larger lines for your in floor heat lines. Also I used some water level float switches and a controller to add water to my boiler (through the return line) when it gets low. This way I don't have to manually fill the boiler.
Currently I am using timers to control when my circulation pumps come on, however you could also use thermostats to keep your house at a good tempurature. Here is a picture of my three pumps. The pump on the right is the hot water circulation pump, and the other two are my two in floor heating pumps.