Hi Dan,
When you are in Step 2 in the Form 2.0 editor (the field details section), you can click and hold on a form field and move it right or left of another (as well as the standard above/below). When you are in the process of moving a field you will see four arrows appear around the field you are hovering over/near. One of the arrows will be highlighted orange identifying where the field you're moving will be placed if you release.
In the example screenshots below, I clicked and held on the form field Last Name and hovered to the right of First Name (notice the arrows around first name and the one highlighted on the right side in orange). When I released the mouse button, the form field last name dropped in right next to first name.
I'm not sure if there is a limit of how many you can place next to each other, but I was able to make 4 columns.
Hope this helps!
Sean