How to write htaccess for a complex site?

Question

htaccess

In general, there is a site, I introduced 1 more directory into it with an almost full-fledged blog, how to rewrite .htaccess for the main site to redirect to a blog that has its own index.php and htaccess.
If you think about it, it's something like yii - backend(frontend+backend) + frontend(frontend+backend)

Answer 1

Generally,

If you think about it

Then it's mod_rewrite