I guess the trick is to add a wix form instead of going through velo, please find the steps below:

1. Add elements
2. Click on contacts and forms
3. Select start from scratch

Now you will see the most easiest way to create a form and add conditions to the same (available on the left)

After creating the form, go to your website and link the button or whichever you are creating to redirect to the form that you craeted