If you don't have your own Pyraminx you can play here with it online. On the screen you can see the unfolded puzzle and the buttons to apply rotations. You can also scramble the Pyraminx or reset it to the solved positoin with a single click.
Solving the Pyraminx online is slightly different from doing it your phisical puzzle because in this case it is unfolded on your monitor screen and you need a good 3D vision to imagine how a rotation affects the tetrahedron. Especially the B (back) turn is tricky.
Under the Scramble and Reset buttons you can see capital U, L, R and B (up, left, right and back) buttons which mark one corner and turn two layers of the puzzle clockwise. For example U turns the two layers under the upper corner. Under these four buttons you can find the same letters followed by an apostrophe. These do the same turns counterclockwise.
Use the arrow or WASD keyboard buttons to turn two layers clockwise. For counterclockwise turns press these keys twice.
Below these are the corner turns which manipulate one piece at a time, the corresponding cornerpieces only.