When I said it was just like controlling a marionette with a million strings, I mean it in every sense of the word. To further emphasize this comparison, I'll just have to paint a clear picture with words.
Consider what someone does when he or she is in the process of cultivating. First, they empty their minds of thoughts that would rob them of their concentration. And once that's done, they will ease their breathing as they tried to meditate and focus on the Qi Energy in their body and the Qi Energy in the surroundings. Once that's ongoing, he or she would then act on gathering those Qi Energy in one place, preferably near the navel so it would be easy to detect and control. And it doesn't stop there! That's just the beginning of cultivation.
Furthermore, every element has a different way of cultivating. Just like how any fruits would have a different taste. That's just how it naturally is.