I assume your electrode is a dual electrode that includes both a glass and reference junction.
Practical Makers shield appears to be an amplifier for pH signals. It doesn't give much info on what the output range is but I guess you can adjust it for a 5 volt full range. I tried to look at the PDF file they had but the link was empty... not a good sign.
Developing a instrument amplifier from scratch, is not something you want to do. If you can confirm that the shield will give you a 5 volt output in the pH range you are looking for, I would advise you to use it and get on with the chemistry rather than spending lots of time on the electronics.