JB just said it all pretty well. There is another way to fire up and engine without A starter but nothing I would ever tell one of my students about. They have seen me do it but it scares most begginers away.
The one post I saw saying to roll the starter before it is on the spinner sent shudders down my spine and I see it done quite often. If the engine is flooded and you do that you tend to bend or brake the rod, not A good thing.
I have started A 40cc gas engine with my old TH standard starter and used it all the time on my RCS 1.40 gas engine. Works great if your battery is fresh and fully charged, I use it every week on my 1.10, 1.20 and 1.40 glow four strokes. I have now gone over to using one of those take along car battery jumpers and it really gives my engines A good zing.