Creating a public page with data from multiple tables

I am moving away from one content management system and into wordpress. I work for a small county, and we provide tax information to the users. The data that is queried is spread accross multiple tables. I purchase the premium “WP DATA ACCESS” plugin and I am trying to figure out how to duplicate the functions that I have in the old system. I started by creating linkage to the main tables which are in a SQL Database through the MariaDB connect function. So, those tables are available. I then went into the query function, and figured out how to write and display the first query (with joins) I wanted to duplicate. Now I need to figure out how to create a page where the customer would type a string to be used in a “where clause” and then display the results using the query I created and the where clause with customer input.

The old web page I am trying to duplicate is an ASP/C# page running in an iframe of a different CMS. The link to what I would like to recreate is https://www.co.richland.nd.us/tax.

Thanks in advance for some pointers.