Adding recent posts with thumbnail to site outside of wp directory

Hey everybody,
I’m relatively new to php, so I could really use some help.

I’m running 2 different WP blogs on my site, one of them with WPTube plugin. I would like to put the most recent posts of the WPTube blog on my main index page along with the thumbnail of the post. I am also using php code on the page for my phpBB forum. Everytime I try to use any WP php code, my site comes up blank. For the other WP blog, I just used a free RSS service to get the most recent posts on the page, however it doesn’t support thumbnails.

Here is the link to the page I’m talking about:

https://www.beer-nerd.com/gateway.php
(to be renamed index.php once I get it working)

Any help would be greatly appreciated!!