How do I get across the broken bridge?

You'll need to find something to fill in that gap.

Of course, that item will have to come from the right half of the screen.

It doesn't look like you have anything large enough right now, so maybe you
should try creating something.

And the only way of creating something is to have Magician do his thing.

Specifically, put a spell on the second and fourth apples from the right.

You'll now need a way to get those apples down from the tree.