By 'reducing the number of CSS and JS files', it probably meant to reduce the number of files for each page by merging them. How many of such files do you have for each page?
By the way, with google Chrome, if you go on the page and open the developper tools (Right-click / 'inspect'), you can generate a performance/SEO report by clicking on the item 'lighthouse'.
By the way, with google Chrome, if you go on the page and open the developper tools (Right-click / 'inspect'), you can generate a performance/SEO report by clicking on the item 'lighthouse'.