To look make an object look at where you touch, make sure you have both the object and the Touch object ready.
You then create the event on the event sheet "On Touch Start", which is found under Touch. You then add the action "Set angle toward position", found under the object you wish to rotate. It will then ask you for the X and Y coordinates for the position. In X put "Touch.X" and in Y type "Touch.Y". That should work!
This will only have the object face your Touch once. If you want it to continually turn to your touch, make the event "Is in Touch" instead.
(Just a quick tip, which I didn't learn until a few days trying, you can set the Touch object to treat Mouse clicks as Touch taps. This is in the properties tab for Touch. This way you can test the program on the computer instead of having to transfer it over all the time!)