As a novice biker, I am curious what you are supposed to do when there
is a stop sign with about 5 to 10 vehicles lined up to get their turn.

Most of the time I have seen cyclists fly by all the traffic right
up to the stop sign. Isn't this kind of dangerous? I know it's
not proper to pass traffic on the right, and I have often seen a
car suddenly pull out (which would be into a cyclist) using a
lane, gravel shoulder, etc to make an impromptu right turn.

On the other hand, I can't see a cyclist entering the queue with
vehicles. At least I don't think I've ever seen this done.

Also, what is the proper way to make a left turn at a typical
busy 4-lane or 6-lane boulevard? Do you keep to the right and
make two crossings?