Making Edits to Existing Templates

I'm trying to make some small changes to the Forbidden Lands sheet template to make it match my homebrew. How do I see the code of an existing sheet and modify it?

You use <a href="https://wiki.roll20.net/Sheet_Editor" rel="nofollow">https://wiki.roll20.net/Sheet_Editor</a> And look up the sourcecode from: <a href="https://github.com/Roll20/roll20-character-sheets" rel="nofollow">https://github.com/Roll20/roll20-character-sheets</a> Guide and info on sheet editing, related to roll templates: <a href="https://wiki.roll20.net/Building_Character_Sheets/Roll_Templates" rel="nofollow">https://wiki.roll20.net/Building_Character_Sheets/Roll_Templates</a>