I can't quote websites; just my own experience making yogurt. The recipe I used was very simple; 1 gallon of milk, between 1/2 and 1 cup of "starter" yogurt, and 1/2 teaspoon lemon juice. I've seen recipes online that call for the addition of dry milk as a thickening agent but I can't recommend that from personal experience.
Because my home-made yogurt had no artificial additives, such as that gummy stuff they make from seaweed, it had a slightly heavier and more liquid texture than store-bought yogurt. If this is a problem for you, it's possible to strain the yogurt through cheesecloth. This removes much of the whey (which can be reserved and used in recipes) and leaves an extremely heavy, creamy product with a texture that resembles sour cream (but tastes like yogurt). Either way, it tasted better than any yogurt I've bought at a store.
You'll want to find a good bacterial culture (mine came from a neighbor who brought it when he emigrated from India) and you'll need to make new yogurt every week or so to keep the culture strong. After a few months of eating a gallon of yogurt every week, by myself, I tired of eating it and stopped making (or eating) yogurt altogether. In retrospect, I could (and should) have scaled the recipe back to half a gallon or a quart. I enjoyed it very much at first (and the process of making it was fun). Good luck!