Inline small JavaScript

What GTMetrix means is to take the javascript code out of those files and adding it into the body of the page (inline), rather than running at the end of the page. This allows the functionality needed at the top of the page to run without having to load the rest of the page first, before loading the javascript code at the very end where most javascript is loaded.

However, these 2 plugins would need the code from the files specified to be taken from the files and added inline, so it may or may not be worth it or easy for a beginner to do. If you do that though, you may need to repeat the process every time you update each of the plugins too – unless the plugins have hooks that allow you to deregsiter their loading of those files in place of your own inline additions.