First, you need to create an encryption key that will be used to secure your content. Click on the "Create Encryption Key" link on the top left corner once you login.
Next, you will need to upload this file back to BitSec. Click on "select" and pick the bitsec.key file. You will need to do this whenever you login if you wish to upload or download files. You may choose to create and use different encryption keys for different files for added security.
Next, click on the second "select" link and browse and upload files to the system!
Once you are done, you may login to https//secure.BitSec.biz from any other computer to download these files. When you are done, simply logout from any machine and your encryption key will be purged from memory. At this point you will no longer be able to upload or download files from any system - until you upload another bitsec.key file.