When in the page/post editor, choose Add Media Button
Click on item in library
Copy the URL address that pops up in the right side bar area.
You can upload image/doc at this point too. After uploading follow the same instructions below.
DO NOT Insert, instead close (X) the library
Highlight the image or content you want to be linked
Choose the hyperlink icon
this icon should show up, but if it doesn’t, it is a picture of a chain link you’ll see in the editor.
Paste the URL address and choose the settings wheel
Check the box “Open link in a new tab” if you want this option
Choose arrow to finish linking action.