Take note that this is a 3 by 3 pyraminx, and the 4 by 4 pyraminx is the master pyraminx. (next page)
There are 3 types of pieces just like the 3 by 3 by 3. There are edges, centers and corners. The tips are the twisted pieces in the image above. The centers are the pieces touching the tips. Centers only have 1 color, 3 to a side. The edges are the remaining pieces. (3 to a side)
A stickerless, speed cube, pyraminx costs $8.96 on Amazon, and a speed cube with stickers costs $7.95 on Amazon. The reason you would want a stickerless is because the stickers won't peel off. WARNING: The pyraminx above is not stickerless. Don't get a cube like that. For what a stickerless cube looks like, go to the 5 by 5 page.
Using the beginner method, the first step is to solve all the centers. (putting the correct ones on the same side) The next step is to twist the tips. Thirdly, you have to solve a side and maybe another one. Lastly, you have to solve the entire cube.
Beginner method: https://www.youtube.com/watch?v=2nvtGjY978Y&feature=youtu.be