Re-organizing the form blocks is simple! Here's how to do it: 

Drag and Drop The Block
Below the settings button of every form block, you'll see another button with two arrows pointing up and down. 

Hold the button and drag the box up or down, depending on where you want to place it. Drop the box to the desired order.

Your new order saves automatically! If your form is already live, you will need to republish it so your changes are updated in the live registration.