Write a
Class GoogleAdWordsTracking {
Variables:
Collect the AdWords id (URL) and put it in a (protected) variable.
Collect other (protected) variables of interest, eg URL to the PDF.
Variables that may return values from some of the class methods.
Methods:
Write the methods you need, like identifying the visitors bahaviour on your site, identifying when a
valid conversion is fulfilled etc. Every conversion have to go via (use) an GoogleAdWordsTracking object (e.g. related to the PHP form). Collect properties in variables returned from the methods.
Database connection.
Connect to a database and (write methods to) put the variables (properties) in relevant fields (columns) of relevant tables. As an alternative, collect the properties in (a) multidimensional array(s).
Analysis / statistics.
Write methods to automize (statistical) analysis (SQL queries etc) on the properties you have collected. Write the necessary (statistical) functions, that is not already implemented in the language you use (C++, Java or PHP). If you use a database, you can automatize the presentation, that is, reporting methods from the GoogleAdWordsTracking class (objects).
Input from the previous posters.
The previous and subsequent posters ideas may give you additional information on relevant class properties and methods.
Hire a IT student.
If OOP is new to you, hire an IT student to do the job / project.
Conclusion.
If you do this thorougly, you may tap into your visitors behaviour and go beyond tracking AdWords conversion. That may be important for your company's digital branding / Advertising in the future. In a nutshell it is about collecting relevant information, properites (variables) and writing the necessary methods (functions / procedures). A class is nothing more than a template, container or pattern if you want for properties and methods. You may need more than one class (that may interact with each other).
This
related post on OOP may give you additional input and relevant references.