Default template – how to edit, change, configure?

Hello, thank you for your time.

I have created a site that uses a static home page. I have also created a blog page that I wish to have display a list of my blog posts. I read a page on the wordpress info center that said you must set the blog page to use the Default Template. I have done this, but it only renders the post titles and seems to add extra content that I don’t want to display (twitter feed from my home page). Here is the blog page. Is it possible to edit/check the Default Template to troubleshoot this further? Where do you configure the php page used for the Default Template? Thank you!