If you buy granola in the store, look at the ingredient list. There are a lot of unnecessary chemicals and additives. You can make your own and control what goes into it. Different ratios are out there but you can experiment with different ingredients.
Epicurious.com says to use 6 parts dry ingredients to 1 part wet. The main base ingredient is ALWAYS rolled oats. When I make my granola I use about 3 cups of rolled oats. Then I add another cup of a combination of nuts and seeds. Some seeds don’t need to be baked (like chia or flaxseed) so you can add them after. I like a mix of almonds, pecans, and walnuts. Other possibilities are pumpkin seeds, sesame seeds, puffed millet, and coconut flakes. Sometimes I also like to add dried cranberries and/or small chocolate chips.
Wet ingredients are what you coat the dry ingredients with. You can use coconut oil, olive oil, canola, sunflower seed oil, or even butter. To this you add some kind of sweetener like honey, agave, maple syrup. Sometimes I add a little powdered stevia to cut on the calories. You can also use an egg white. You can also add cinnamon, vanilla extract, nutmeg, cardamom, or salt for flavor. TheKitchn.com suggests a 50-50 ratio of fats to sweeteners.
Once you coat the dry ingredients with the wet ingredients, you can spread it out on a sheet pan and bake at 300 degrees for about 30-40 minutes. Remember to stir every 10-15 minutes. After it is done, cool completely and then you can add the dried fruits of your choice such as dried cranberries, cherries, raisins, apricots. Store in jar or airtight container. You can use this as a cereal or mix in with your yogurt.