The best place to start on blades is to do a search on scroll saw blade chart and go to images. There are lots of them. It will tell you what size is intended for what thickness of wood. The blades you get with your saw are probably not very good blades, nor are ones you can buy at most big box stores. Probably the most common ones used are Flying Dutchman, Olsen, and I am reading good comment about Pegas blades. It is hard to tell a person what to use, because it is personal preference. When I started I purchased a combination set from one of the vendors and tried different ones. That got me into the ball park of what I like. I kept experimenting from there and now know what I like although I still try different ones just to see. The is probably the most common question from beginners, and there are lots of answers. Do not let it intimidate you, you will get a feel for what works for you as you go along.