If you want to control the design and flow of your funnel yourself, choose Custom Funnel.
You will notice that you can also choose the page template at the funnel design screen. However, you can change the page template any time later as well.
In addition to that;
You can use these buttons to add or remove pages from your funnel flow.
Make sure to give your funnel a nice title.
and hit "Create Funnel" button.