Updated:
I now see the post you linked to is the API Cookbook.
What you describe can be achieved simply by building a report in the table where these records exist and create filters set so that field ID# 13 ="High" and field ID#12 is not equal to "Completed" and then to only show fields 56, 6, 67 and 10. Note that in the Report Builder you will make all these field selections by the Field Name, not by the Field ID#.
When you build a report like this, you can actually access the URL that is generated by clicking on the MORE when displaying the report and choosing the last option "Show the expanded URL for this report" which will show you the construct of the URL.
For what reason are you creating a code page?
Feel free to reach out to me using my profile
https://quickbase-community.intuit.com/users/537-quickbasepros_ids if you need some assistance on Monday.
