There's nothing to explain.
This answers your first question.
In the file wamp\alias\phpmyadmin.conf you replace the time limit values with the ones you want, for example :
php_admin_value max_execution_time 1800
php_admin_value max_input_time 1800
you save the modified file then you launch PhpMyAdmin by its link in the localhost page or by left-click -> PhpMyAdmin
and the time limit for PhpMyAdmin will be the one you modified previously even if in the PHP settings you still see the old value :
Left-click -> PHP settings -> PHP settings -> max_execution_time = 120
I have done this dozens and dozens of times, as well as to increase the maximum import sizes via
php_admin_value upload_max_filesize 1024M
php_admin_value post_max_size 1024M
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