>>2718477The thin ones are quarter inch. Some packs have half inch tubes as well. They obviously carry more water and is better for longer systems with more connections. If you have a garden that is larger than... Say ... 8'x4', you may want to find a kit with half inch tubing as well. They'll usually have both. They come with instructions and there are lots of videos. It's basically Legos, things will fit where they are supposed to fit.
