Can I use the images?
The images are just samples and are not meant to be used (otherwise we would all have the same covers). You should look for your own, similar photos that fit your story better and use the templates to get the style, colors and fonts right. The guide lists some resources for finding images and cover art.
Where can I find the fonts?
I used a lot of fonts in these templates, some free and some paid. Just because I included them doesn't mean you necessarily have the rights to use them on your book cover (I can't transfer my licence rights to you). Many of them are free, but you should check the font you want to use and make sure you pay for it if necessary (or just switch to a free font, there are lots).
How do I make a Kindle cover?
Kindle covers are usually JPG - these templates are built for 6x9 @300DPI, which will make them about 1800px wide, a good size for Kindle and ebook retailers. You'll have to save the Word files as a PDF and then use an online PDF to JPG converter. If it doesn't work well, try another method of saving as PDF (Word to PDF conversion tools, or print-as options, and also other PDF to JPG conversion tools). If you have a high resolution screen, you can also take a screenshot of your cover. For the online tool - just save as PNG and it should be ready to use.