Striker / Child-Theme

Hello; Regarding the Striker Theme.
I am not a code person, developer etc. – I just follow specific/detail instructions & advice. Because there is a logo with specific colors and fonts, I was told to create a child-theme to keep these customizations intact even after any updates to the Striker theme.
I have created a child-theme using the style.css file. I also noticed that there was a css folder with the four different color themes, which I also copied into the child-theme folder.
Currently, the child-theme is apparently connected to the full-width.php template. I prefer to use the custom-home-page.php template.
Specifically, how do I have the child-theme point to the custom-home-page.php template to have the margins on each side?
I was not aware that I had to do anything with the php files. This is becoming a lot more complicated than I had anticipated in order to keep my custom styles intact with any theme updates. Advice is welcomed.