Hello!
First of all you shouldn’t touch any files directly on the parent theme.
So first, you should upload and activate the child theme that is inside the zip you downloaded once you purchased the theme.
Then you should create a new file inside: YOUR-CHILD-THEME\inc\templates\affiliates and name it “affiliates-single-style1.php”.
Then go to parent theme folder: pokatheme\inc\templates\affiliates\affiliates-single-style1.php, and copy-paste all code from this file to the new file you created inside your child theme.
Finally go to the 3rd line and change this:
<div class="row gap-20">
to this:
<div class="row row--reverse gap-20">
Let us know if you still need help on this one.