You can easily add a button to the menu bar in Fintech manually. Just for reference this is what we mean by that on the main demo:

1. Go to Appearance > Menus - click Screen Options at the Top and ensure CSS Classes are ticked.

2. Next, click the down arrow on the menu item you wish to make a button and add some extra classes to the CSS Classes field within it.

right button see-through

Note: If you leave out the see-through bit, you can make the button a solid color.

3. You can change the color of the button as well as the hover color within Theme Options > Colors