From here, you have the ability to:
Upload new files - click Upload Files
Delete files - select an image and click Delete File
Viewing file details - select the desired image and the viewing information will appear in the upper right-hand corner of the window. Notice, in the file 'details', a custom URL is displayed for each file. If you need it, you can use this URL to link to a particular file from anywhere else on the site!
You can also create Collections of files (essentially separate photo albums) by clicking 'New' under 'Collections.' From there, name the collection and add the file you would like displayed in the collection.
Adding Uploaded Files to your Site
First, from the Pages section, select the page where this file will be available. Once selected, click 'Edit' in the upper right corner. From there, click the 'Add a block' button to bring up all of the content blocks, and drag the 'Download' block onto the page.
Then, choose 'Select Existing' to choose one of the collections you've previously uploaded, or choose Upload New!