Ok - let me sum up and clarify:
1.If I modify things within existing customisation options in the parent theme, future updates are not destructive either to my widget or setting or other similar configuration. Only if I choose to modify its elements BEYOND the options of the parent theme, your suggestions seem to matter. Right?
2. I've spent a lot of time preparing some plugin configuration. Suppose I started with a child theme, I hope these are still relevant and active: sharethis, FB for WP, Akismet, Google Analytics, SEO stuff, XML Sitemap and the like.
3. Now, when I create a child theme and work on it, doing any changes to its style will or will not endanger my current config, like the above mentioned?
4. i understand the benefit is also that changes to the parent affect the child in a positive way, with all possible improvements?
5. In my host I work on Direct Admin platform with Installatron tool, so I guess most of these steps are easy to do
The child folder should be in the directory, not inside the parent theme folder?
@import url("../twentytwelve/style.css"); < i place of dots, I should paste my blog url?