To publish your contact form, first save your form. Then copy the auto-generated shortcode present at the top of the screen as shown below.
Go to Pages>Add New. Add a title of your choice to your form and then paste the shortcode with ctrl+v on the body.
Click on Publish.
You can view the published page either by clicking on the Permalink just below the title of the form.
Or you can click on View Page as shown below.
This is how your contact form will look from the frontend: