Content covers header and menus when scrolling

Hi,

I am somewhat new to WordPress and am having a problem with the content covering my sticky menu header. I added an image in the content on my homepage and a testimonial block below it. When I scroll down the content goes over the header and the drop down menus in the header.
I am using the Flash Theme and can not figure out what to do. I am not a coder. I tried adding code I searched for on the internet to the additional css section but that didn’t do anything. I looked at the Theme header php and the css page in the Theme editor but I don’t find anywhere to add the code snip it to.
How do I get the content to go under the header and top menu?
https://fpm.369.myftpupload.com

The page I need help with: [log in to see the link]