I've been tearing my hair out with this Theme and the pagebuilder plug-in for hours. Could not get the post widget to display thumbnail images wihtout having this huge image pop up on the post page (the codes in a php file). There's apparently no support from the guy who wrote this and his reply emails say he gets back to people in 2 days which is horrible support. So I'm trying this forum even though I paid for the upgrade and it's supposed to have support (yup, I'm frustrated with this company). Anyway . . .
I think if you go to APPEARANCE > CUSTOMIZE you'll find the settings for the menu. But transaparent isn't an option.
Try this for the initial transparency of the menu.
APPEARANCE > CUSTOM CSS
background: none transparent;
margin: 0 -35px;
min-height: 35px; /* For when the menu becomes a sticky menu */
This will make your menu transparent. I found the code in the style.css file, then copied it, pasted it into the Custom CSS file and just changed the background color from what was in there to the none transparent;
Hope it works for you.