Don't have a real Megaminx? Play online with this simulator! You can apply any basic rotation clicking on one of the 12 fields or the allocated buttons. This will turn one face clockwise by one fifth turn. You can do counterclockwise rotations only with the 12 blue buttons with numbers on them followed by an apostrophe. No need to try, the drag and drop rotations are not working :) ...maybe in the next version they will.
You can also use the Stefan Pochmann notation to scramble the dodecahedron. Using only with the R++, D++ and U bottons you can access all the pieces, including the centerpieces. Just mentioning that the ++ means that there are two fifth turns applied. The Y key turns the whole cube around its vertical axis. All these operations presented above are available in clockwise and counterclockwise directions.