Auto-populate text from check box description

I need help with auto-populating text into text boxes based on which check box is selected. 

Here is a generalized look at what the document says: 

(Check Box) Individual form emailed PDF 

(Check Box) Group Form in Excel

(Check Box) Electronic via Excel

You have selected the format: 

_____                  _

The delivery method chosen is: 

______                _

I want the ability for it to auto-populate the text on the two blank lines like in this example .. if they checked box #1 it would look like this:

(CHECK) Individual form emailed PDF 

(Check Box) Group Form in Excel

(Check Box) Electronic via Excel

You have selected the format: 

_Individual Form_____

The delivery method chosen is: 

_emailed PDF ______

Can anyone help with the formula?