Creating a Child Theme from a Modified Existing Theme

I am trying to create a Child Theme from a Modified Existing Theme and I see the codex steps as detailed here: https://codex.www.ads-software.com/Child_Themes#Creating_a_Child_Theme_from_an_Unmodified_Parent_Theme

However the steps are not given in much detail here so I was wondering if there a resource online which gives more clear directions or if you guys could tell me. I am very anxious about trying it and then losing all of my modifications.

I am currently running wordpress on a localhost. So the first step is to:

1. Make a backup of your customized parent theme using FTP, SSH or your Web Hosts file manager. You’ll need this if things don’t work out and you need to revert.

As I am on a local host can I just do this by clicking export in the dashboard, which does the following:

“When you click the button below WordPress will create an XML file for you to save to your computer.

This format, which we call WordPress eXtended RSS or WXR, will contain your posts, pages, comments, custom fields, categories, and tags.

Once you’ve saved the download file, you can use the Import function in another WordPress installation to import the content from this site.”

and then back up the sql database in phpmyadmin.

Is that all that is needed for this step or is there something else I am missing.

Help would be GREATLY appreciated.

Thanks!!!