At a guess, you're using Windows and the author is using Mac? [1] (I'm also using Windows -- it's my gaming PC, don't judge! -- and having an equally difficult time.)
Definitely don't let anyone ever judge you for that. The vast majority of desktop/laptop users are on Windows, including a slightly-less-vast majority of developers.
For this little project, I just grabbed a template used by a very popular Github page. Looks like the font does not play well with Windows. I just switched it to good ol’ reliable Helvetica.
Yes, and that font looks much better. I've used Lato on projects in the past and it was legible, but you have to stick to 400 weight and above (IIRC, that template you used was only loading 300 and 700).