Created Custom Template [pdb_List] now what?

Hello, great plug in! I am new to PHP, please bear with me.

So basically, I want to create a custom search with multiple dropdown menus. This website does exactly what I’m referring to https://www.pacproperties.com

I have several property listings and would like the ability to search them by CITY (Los Angeles, Long Beach, etc) and # of bedrooms (studio, 1,2) and pets ( checkbox yes/no)

I created a /wp-content/themes/YOUR_THEMES/templates/pdb-list-detailed.php template, and have read all the forums and documentation, but now I am at complete loss what to do next.

here is the code from the pdb-list-detailed.php template:

<?php if ( $filter_mode == 'filter' || $filter_mode == 'both' ) : ?>

    <fieldset class="widefat">
      <legend><?php _e('Search', 'participants-database' )?>:</legend>

      <?php
        /*
         * there are 4 options for this function which defines which fields will be
         * available in the search dropdown selector:
         *    1. "all fields" text: set the text of the default "all fields" item:
         *       leave it "false" to use the internationalized defualt
         *    2. print it or return the element as a value: only use this if you
         *       need to alter the HTML directly. You will need to print the item for
         *       it to be seen. If 'true', the function prints the selector dropdown.
         *    3. columns: supply an array of column names if you want to define the
         *       list of fields that can be used for searching: 'false' uses all displayed
         *       fields
         *    4. sorting: you can choose to sort the list by 'column' (the order they
         *       appear in the table), 'alpha' (alphabetical order), or 'order' which
         *       uses the defined group/field order
         */
        $this->column_selector( false, true, false, 'column' );
      ?>

      <?php $this->search_form() ?>

    </fieldset>
    <?php endif ?>
    <?php if ( $filter_mode == 'sort' || $filter_mode == 'both' ) : ?>

    <fieldset class="widefat">
      <legend><?php _e('Sort by', 'participants-database' )?>:</legend>

      <?php
      /*
       * this function sets the fields in the sorting dropdown. It has two options:
       *    1. columns: an array of field names to show in the sorting dropdown. If
       *       'false' shows default list of sortable fields as defined
       *    2. sorting: you can choose to sort the list by 'column' (the order they
       *       appear in the table), 'alpha' (alphabetical order), or 'order' which
       *       uses the defined group/field order
       */
      $this->set_sortables(false, 'column');
      ?>

      <?php $this->sort_form() ?>

    </fieldset>
    <?php endif ?>

  </div>
  <?php endif ?>

<?php
  /* END SEARCH/SORT FORM */

[Please use the code buttons when posting code here]

how can I edit this code to make it have multiple search dropdowns?

I have read all the forums and the thing on creating custom templates here and I am so LOST!

also, are there any great php websites out there for absolute beginners? Thanks in advance!

https://www.ads-software.com/plugins/participants-database/