Page template not visible in properties dropdown

Hello everybody!

I want to use an existing html-page as frontpage for my blog.
I followed this good-looking advice closely:

https://codex.www.ads-software.com/FAQ_Working_with_WordPress#How_can_I_have_a_static_front_page_and_posts_display_on_a_page_called_Blog.

Mainly I created a page template by putting these as first lines of my former html page:

<?php
/*
Template Name: MyFront
*/
?>

I then saved it as: root/wp/wp-content/themes/default_deleer/ myfront.php , (default_deleer being my active template).

Now I should be able to assign a template called MyFront in the dropdown menu when writing a page, shouldn′t I?

I wonder if wrong location of the files might be the cause for the problem???

What I′m still unsure about is where my website content actually belongs.

(I′m operating WP locally under “Usb Webserver 7.0” from https://www.usbwebserver.nl , that works fine as far as I can see.)

Currently I have ALL files BOTH in the above mentioned directory AND in Root/wp
I guess the latter is the directory that works,just because WP was accessible only after I copied the files to Root/wp but I′m not sure.

Fact is that none of my self-created page templates shows up as an assignable template.

Where is my mistake???
Thank you in advance for your help!

Greetings, Maddin01!