Hi,
what i did was copy page.php to my child theme root.
rename the file to any name you like but end the file with ‘page’ so you know
what it is for example: test-page.php
Then open the file up and replace the comments with the following
<? php
/*
Template Name: test-page
*/
?>
save the file, reload your page.Under page > add new page
template should appear on the right.