Go back to the previous paragraphs and click those if you don't know them yet. The essense of projectile motion is that the vertical components are the same as free fall, and the horizontals are the same as constant velocity. Normal forces, friction forces, weight, various tensions and compressions . The theta will show up as q, pi as p, etc. Incidentally, some of the simplest ideas cause the most trouble.
All forces come in equal and opposite pairs, for example.
Once you get the hang of it, this is a really simple concept. But you might have to work hard at ridding yourself of some wrong-headed notions about force. It is something like being in the habit of misusing lie and lay but with more serious consequences. Bad habits are hard to break, so work on it. Think about the force on the insect due to the car, and the force on the car due to the insect.