Responsive 1.7.4 to 1.7.5 upgrade

I have a few questions about installing the new update. I have a slightly modified Responsive 1.7.4 theme and just saw the 1.7.5 update appear. To retain modified theme I see that I should create a child theme and found your post responsive-child-theme.zip. Do I install and activate the child theme then make my necessary modifications like my current modified parent theme and do I leave the child theme activated? Also, do I permanently leave the parent theme and continue to update it when you release updates?

https://www.ads-software.com/extend/themes/responsive/