Looks like you worked it out and I sent you a DM.
The form is not editable (i.e. you will see it in view only). This is because we didn't want people changing formulas and messing the sheet up.
If you follow the help document you'll see that there is a Google Form. When you submit this for the first time your user will be added to the table showing your current progress. If you need to make updates in the future there is an auto-generated link in your table row which will open a pre-populated form where you can just change the necessary information and resubmit