The child-theme is included in theme package townhub-child.zip file ( downloaded with All files and documentation option )
Just upload the .zip file to WordPress admin -> Appearance -> Themes screen to install child theme, as TownHub parent theme
Then active the TownHub Child theme
It’s done.
Then you can add modified code to your child theme files. It will be safe with updates. You can also override TownHub theme and TownHub Add-Ons .php files from child theme folder. Read the documentations bellow for more details