MATLAB: How to take in handle to pre-existing object using GUI/GUIDE

guiguidehandlesmatlab gui

I'm working with GUI/GUIDE where I have created a GUI that lets me edit the properties of an object of a class I created called "Task" using some text boxes. When I create a "Task" object within GUIDE the GUI works as expected. My problem is that I am unable to take in a pre-existing object and edit in my GUI. How do I take in a handle to a pre-existing object?
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