I currently am developing a webapp and I haven't used OOP techniques at all and I'm starting to get overwhelmed with unmanageable code. I've decided to convert this project into an OOP design. My problem is that I've never done OOP before so I don't quite understand the logic about when or what to make objects. I know what OOP is and how to make classes, I just don't know what objects to make.

For example, look at my current webapp:

Would you make one class called "Record" and make methods to do actions on the source, processing, bagging, grading and finished product stuff or do each of those go in their own class and objects with methods to do actions on each. I just don't understand where or what to make my objects.

This will be my first time doing OOP. Hopefully someone can clear this up for me.