In the Library window, click on the Add a new Document button.
In the form, Select the file source and select the file you wish to upload.
You can set an optional Title or leave blank to use the filename as the title. You can also select a Document Category to organize your documents.
Once you have chosen your file, and made any title/category changes you want, hit the Save button. The file will now appear in your list of documents and be visible within a few minutes to your mobile app users.