Once you've clicked "Edit" on your Canvas Page.

To launch Design Tools use the keyboard shortcut (Alt + Shift + D) and it will appear on the right hand side of your browser. 

Select the text that needs to be updated, then use Design Tools to edit the link. 

You'll click the bulls eye
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Find the link that needs to updated and you'll paste the updated link in the space that reads URL (highlighted in yellow)

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