How do I set the conditional field to go to the next step

I have conditional fields pro running on this website and I want the form to go to the next step as soon als someone selected something in the first step (it’s one pull-down menu) automatically, so without using the next button.

How do I get the form to act that way?

I know how to edit .js files but I can’t find the right code to get it to work.

If you go to the link please click on the link to get the pop-up to open with the form.

thanks in advance for your information.

The page I need help with: [log in to see the link]