When you're logged into the candidate portal, click "my documents" in the top red bar navigation bar. This will pull up a menu with two choices one for "resumes" and one for "cover" letters. Click on the one you want to upload.
Once you click the link you will see the option to upload a resume. Click the button which will take you to the page you see below. Find the choose file button which will create a popup allowing you to choose the resume off your computer. Once you've selected it and uploaded it, click upload resume.
Congratulations! You have now uploaded your resume and will be able to select it when applying for jobs. Click the Proven logo in the top left of the screen to return to the list of open jobs.