I need to combine three external CSS files to speed up my website. As instructed i have to remove the calls to the old CSS files. Where to locate the call to my three external files? The three external files image attached.
One is call for Google font, not a css file. You remove it if you don't need the font. I haven't used WP for a long time but you should find header.php in appearance\editor
However, changing the code directly will not be kept if you update the theme. I would actually suggest installing some sort of css/js minifyer plugin - some of them combines and hosts on your host.
First one is css file used to design your website. You can edit this files to speed up. Second one is google fonts. You can remove this link if you don't need those fonts. Third one is WordPress's css. So you can't edit or remove.
I need to change/remove some CSS call links. I can see them in View Page Source. How do I actually get to them to make the changes? In other words, where are they?
They will be in different places based on where they're coming from. And, as you've already been told, if you change something manually, those changes will be nulled when that plugin or theme is updated. You're using WordPress. Unless you want to do these changes every time you update, do as I suggested earlier, find a plugin to combine, minify and optimise css and js.