single site migration

Hi, I want to migrate a single wordpress site from one server to another. I am using the steps suggested on this post https://premium.wpmudev.org/blog/migrating-wordpress-and-multisite/ but it prompted to download something from the server when I previewed it on the browser (https://64.91.249.169/~w3llndtrulyc0ma/) . I tried to disable the .htacess and I can view the file directory and folder already but it seems that the theme is broken.

What is the best way to migrate a site then? Any help help or advice is highly appreciated.

Thanks.