Hint: Any symmetry of the tetrahedron must map vertices to vertices, and is completely determined by this mapping from vertices to the vertices. Label the vertices $A,B,C,D$ and consider the permutations of these vertices. Eliminate those that do not correspond to geometric symmetries of the tetrahedron. For example, if you rotate the tetrahedron so that $A$ and $B$ exchange places, then $C$ and $D$ also exchange places.
Since each symmetry is completely determined by its action on the four vertices, once you have identified the permutations of the vertices, you can forget about the rest of the tetrahedron and think only about the permutations.
Obtain an actual tetrahedron; tetrahedral dice are available online or in game stores. If you can't find an actual tetrahedron, make one. If you can't make one, find a cube (such as a die) and color four alternate corners with a red marker. These are the vertices of a regular tetrahedron, and any symmetry of the tetrahedron is therefore also a symmetry of the cube.
Hint: Any symmetry of the tetrahedron must map vertices to vertices, and is completely determined by this mapping from vertices to the vertices. Label the vertices $A,B,C,D$ and consider the permutations of these vertices. Eliminate those that do not correspond to geometric symmetries of the tetrahedron. For example, if you rotate the tetrahedron so that $A$ and $B$ exchange places, then $C$ and $D$ also exchange places.
Since each symmetry is completely determined by its action on the four vertices, once you have identified the permutations of the vertices, you can forget about the rest of the tetrahedron and think only about the permutations.
Obtain an actual tetrahedron; tetrahedral dice are available online or in game stores. If you can't find an actual tetrahedron, make one. If you can't make one, find a cube (such as a die) and color four alternate corners with a red marker. These are the vertices of a regular tetrahedron, and any symmetry of the tetrahedron is therefore also a symmetry of the cube.