Where can I access my custom page template?

May be something is wrong on your page template file. Have your added page template name at top of the page like this:

<?php
/*
Template Name: My Custom Page
*/

Try with this and check once again. You can check WordPress document for creating custom page template. Check this link: Page Templates

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)