I want to add granted spells to Warlock subclass, not optional spells to the spell list. I can't for the life of me figure out how to do it. I try to add them in different ways and then check back on my character's spells but the spells just wont show up. Anyone know how this can be done?

You mean adding additional spells known the same way that the Aberrant Mind and Clockwork Soul Sorcerer subclasses add spells? The easiest way to learn is by creating a sorcerer subclass using one of those two as a template so you can see how those were programmed and then duplicate it for your Warlock subclass.