ODK Collect: Force validating text responses in sequential questions

Hi Everyone - I'm working with a form that requires the participant to enter an alphanumeric participant ID, right now I have this set as a 'text' entry. I want to make a subsequent question asking the participant to re-enter their ID to ensure it's the same as the ID in the previous question (similar to how you're sometimes asked in online forms to re-enter your email address and it gives you an error message if the entries aren't identical). I would similarly like for there to be an error message if the entries are not the same between the two questions - is this possible?

I'm using Excel on Windows 7 and will import this form into ODK collect to be used on a tablet for data collection.

Thanks in advance!

I figured it out.

In the constraint column I entered:

Thanks and hope this helps others