Once you log into the editor follow below steps.
Click update content
Highlight the section or wording you want to link with new file and click hyperlink button
Browse for the file you want to upload or link to
If the file is already in the web site you can find it from the right-hand side file list.
If not upload new file by clicking Choose File and then click upload button.
If you want file to be open up in a new window select Blank from the drop down and click Apply and then press OK button.
Click save button on the page to save content