1. You will need a food processor or blender to puree the tomatillos for the sauce and you will also need a large oven proof heavy bottomed pan (like a Dutch Oven) to cook the chili in.
2. This chile recipe is not particularly hot so if you want to make it hotter you could add a couple of seeded fresh Jalapenos (or hotter chilis if you're game!) to the food processor with the tomatillo sauce, or simply add some hot sauce or extra chili powder. My family will not eat it if it's very hot so my recipe reflects that.
3. ANAHEIM PEPPER SUBSTITUTIONS
Anaheim Peppers are regional and may not always be available in your area. Sometimes they are called New Mexico Peppers so you could look for those. Poblano peppers (they are long, skinny, and green) will work instead and they should be more widely available