I believe that what your TA is trying to say by drawing 3px, 3py, and 3pz orbitals is by drawing a bell shaped on those axis. For instance, for 3px you will draw the bell shape on the x axis, 3py on the y axis, and 3pz on the z axis. These orbitals is where the electron will lie.
After you draw the bell shape on the attended axis, then you will draw the nodal planes, angular node, radial node, etc. We know that in the nodal planes and etc., there is 0 probability of electron density. You get the nodal plane by doing n-1, which in this case (3px,y,z) will be 3-1=2. This means you will have 2 nodes in your figure. You will have the angular node ( which is just a straight line through the dumbbell figure) and a radial node (which is the shape of a circle in the orbitals).
I'm sorry if this sounds confusing, it is hard for me to explain without a picture. But I found this video very helpful! https://www.youtube.com/watch?v=wkrAtD1mp7k