Child Theme concern

Hi guys,

I’m relatively new to creating a website, about wordpress, themes, etc. A “child theme” is alien to me. I just initially followed what made sense to me which was to install your theme and proceed in developing my site. After more than 2 weeks of tinkering, I’ve just found out that using a child theme is A MUST.

Without using a child theme, updating the theme may result to a huge mess if we’ve done some CSS changes in the theme, etc.

My concern:
Now that I know I should use a child theme, how can I integrate it even after all the changes that I’ve already done for my site?

Thanks in advance. Hope this would also help some of the beginners here like me. 🙂