Upload Files
You must be in the Build tab to upload files.
Method #1: Files can be uploaded from any page that has the Add File button. This will add a link to the selected file(s) directly to the page you are working on. 
Click the ActionsLink next to Add Files.
Then click Browse for Files.
This opens the Content Browser window.
Click My Computer to access your hard drive.
Find the file/files you wish to upload and click Open.
Method #2: Uploading files through the File Manager gives better control over file organization.
Click File Manager from the Designer Menu.
Use Create Folder when new folders are needed.
Files may be directly added here by clicking Get Files.
If files need to be in a particular folder, click the folder and then click Get Files.
Get Files opens the Content Browser described above.