finding my way around CSS Gallery theme

HI All,

I am an old had at web design / development, but a new hand at WP. I am using CSS Gallery theme at https://www.visionbyamit.com/wordpress.

I would like to know:
1. where is the “index” page for all of it and what is it called? I saw an index.php file, but it only had two lines of code.

2. As you will see by looking at the page the newest post is the one closest to the top left corner of the page. I would like older posts to rise up, where do I change the date of the posting in order fool WP to thinking it’s new?

many thanks for your help.
A