Backend Issues

I am having some issues on the backend of my website (ryanhurdlive.com). I am including a screen of the issues listed by Google PageSpeed Insights. I have no web design experience and would have no idea where to begin fixing these issues. Avoiding these sort of issues is one of the main reasons I purchased a premium and highly rated theme. I have gone through the HighEnd documentation and have installed the recommended plugins but those do not fix HTML, JAVA, CSS, and issues with Prioritizing Visible Content. These issues are amplified even more on mobile side where I am clocking a 55/100 speed. Would love some help correcting these issues.