Tap Repository and then you can tap to drill-down through all the content available to you. The repository is particularly useful if you want to find content outside of site document libraries, such as in wikis.
Sites are where content is directly stored and are the quickest way to access content. Tap Sites and you’ll see a list of sites that you’re a member of (My Sites) with the account you’re currently using. You can filter the view of sites you see to your Favorite Sites, or use the Site Finder to search for sites.
Tap next to a site for options to join or leave a site, favorite/unfavorite a site that you’re a member of, and view the site members.
If you have multiple accounts set up, first select the account you want to use. Tap on a site to view its document library and navigate through the folders until you find the item you’re looking for.
See Searching for more on finding content.