How to tell the user that some form fields can not be changed later?

I have a form wizard input fields. In the first step of the wizard, there are 2 checkboxes that, once submitted form, can not be changed. All other fields can be modified later if the user wishes.

How can I tell the user that the two checkboxes can not be changed so that they do not miss the message? Is the following message understandable?

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