I would like to change Pages into Posts

I am customizing the ChaoticSoul 1.0 theme: https://themes.wordpress.net/columns/2-columns/134/chaoticsoul-10/

On index.php I would like to change the code that calls the first blog post as the default index material so that the first page listed under “Pages” is the default instead. Could someone show me the proper code for calling the first page instead of the first post? The pages will serve as blog post instead of the usual method of posting. There also will be no Archive or Catagories (both of which I have commented out).