Put this command in the command block the player activates.
/tp @p # # #
For the #s, go to the point you want them to teleport, open your F3 screen, and look for the X Y and Z coordinates.
Replace the #s with X Y and Z coords in that order.
Let's say I want to teleport the person who steps on the pressure plate connected to my command block to point 275 X, 64 Y, and -72 Z. I would simply put this in the command block:
/tp @p 275 64 -72