You don't need to remove the hood to adjust it. If you have Shimano shifters, and you look carefully on the sides of the shifters, there will be a kind of indentation that looks like a tool is able to be seated in. Thats where your allen key goes in. Its usually a 5mm key, and you need to only pull back the front of the hood a little bit to get the key underneath and find the bolt. Loosen this bolt, then just twist it and tighten it once its in position.