Sponsors can be edited under _includes/footer.html.
Sponsor logos can be managed under assets/logos/.
Profile pictures, blog photos, and general photos are under assets/photos/.
"Blog Posts" can be edited under _posts/.
"Pages" can be managed in the root. Simply add a <name>.md file. Files in the root should use the following header block:
---
layout: page
title: Capitalized Title
calltoaction: (This is optional, but is the smaller text in the same block as the title text.)
permalink: /title-but-web-friendly/
---