Since you say you're a beginner, are you easing up on the pedals when you shift? It's normal for an upshift (to a smaller cog) to sort of "clunk" into position if you're putting pressure on the pedals, especially if there's a large-ish gap between the two cogs. My 5 speed does it, and so does my 20 speed road bike, within reason.

Do you ride any other bikes for comparison? Next time you ride, try shifting without any pressure on the pedals. If the chain slips into the higher gear smoothly under no pressure then it sounds perfectly normal. The crank shouldn't jerk forward so much that it causes problems, but honestly it sounds like you're just shifting under power and aren't used to the feel of shifting.