The bobbin turns on its own tempo to wind the thread (bobbins groove for thread has it's own diameter, does not need to be the exact same as the flyer). The whorl goes at another tempo to make the twist in the thread. You can adjust the tempo for more or less twist You'll notice the ' pull' on the thread when you tighten it, the pull becomes more, so you either spin faster, or the thread is more twisted before it winds on the spool. The little hooks are only for dividing the thread equally over the spool, but you'd figured that out already of course. There are often two or more disks with grooves belonging to the whorl, you'll notice the difference in diameter. You can hook up the thread onto one or the other depending on how fast you want to spin. Tighten up the thread / snare afterwards by turning the handle on the front. To ensure the snare or thread is kept on a good tension, you need to have one continuous loop, divided in two loops, like with the rope games you played as a child. One loop goes over wheel and bobbin, the next over wheel and whorl, the thread crosses itself preferable on the bottom and is sewed together there, see pictures . I hope I make sense, it's a hard concept to grasp, in the category of ' just do it, don't figure it out'

And english is obviously not my native language, but I hope it answers your question, if not somebody else may feel free to help.