You can reveal Submission Form using any element on page (eg. button, link or any media). Just add to HTML of this element special class
.aet_submission_form_trigger_* where asterisk is form number ID.
<a href="#" class=".aet_submission_form_trigger_1">Press me</a>
Plugin script will attach opening function to any element with this class if it finds such.
You can find Form ID on options page. Default trigger class is located in Submission Form Settings panel block:
You can replace default trigger class with your own, in this case submission form will open on click of elements that has your class.
You can use any valid CSS selector with class name, id or attributes selector. Read more about CSS selectors here
Tip for menus
In WordPress on Appearance/Menus page click Screen Options in upper right corner and choose CSS classes in Show advanced menu properties.
Then edit menu item and add
.aet_submission_form_trigger_* class or your custom selector.