One of the simplest and most useful lens combinations is the astronomical telescope (below).

Another way to think about this is to add an "eye" at the far right to look through the telescope. The eye is a third lens and a "retina". The object for this third lens is the image formed by the second lens, so if that image is at infinity, it will be focussed nicely onto the retina (the relaxed eye can easily form images of things far away). Again select the source and drag the rays around to see how angle translates into position on the retina. The eye is seeing the image of distant stars as points, and their angular separation is magnified.