Duplicate META tags

[mexabet]

I have this script and it works fine but the dynamically-generated URLs have duplicate title tags and duplicate meta descriptions- having inherited that from /cmp/index.php.
A few examples of the pages are as follows:

/cmp/index.php
/demo/index.php?start_time=12.00+am&start_tz=Africa/Abidjan&end_tz=Africa/Abidjan
‎/demo/index.php?start_time=12.00+am&start_tz=Africa/Abidjan&end_tz=Africa/Accra
/demo/index.php?start_time=12.00+am&start_tz=Africa/Abidjan&end_tz=Africa/Algiers

The following is the section of the code causing the duplicating issue:

// Check to see if the form has been submitted
if ($_GET["start_time"] != NULL){
    $start_time_input = htmlentities($_GET["start_time"]);
    $start_tz = $_GET["start_tz"];
    $end_tz = $_GET["end_tz"];
    putenv("TZ=$start_tz");
    $start_time = strtotime($start_time_input);
    echo "<p><strong>";
    echo date("h:i:sA",$start_time)."\n";
    echo "</strong>";
    putenv("TZ=$end_tz");
    
    echo "in $start_tz becomes ";
    echo "<strong> ";
    echo date("h:i:sA",$start_time)."\n";
    echo "</strong>";
    echo " in $end_tz.</p><hr />"; 

Below is an example of the search result result:
01:00:00AM in America/Los_Angeles becomes 04:00:00AM in America/New_York.

The search result is generated by a search query through a web form, which works fine.

My question now is how do I use this dynamically-generated results, such as "01:00:00AM in America/Los_Angeles becomes 04:00:00AM in America/New_York." as the title tags of the generated URLs? And how do I assign META Keywords and META Descriptions to each generated URL?
Finally how do I assign SEO friendly URLs through MOD rewrite?