301 redirect for different permalinks structure

hey

i need to redirect my old blog to my new one

the old one is hosted at https://www.mydomain.com/blog

and the new one is in the root of https://www.mydomain.com

now, google indexed my old blog under that old address with permalink structure as follows

https://www.mydomain.com/blog/post-title/

and my new blog uses other permalinks structure

https://www.mydomain.com/post-title,000,keywords.html

the content on the new blog is a copy of my old blog + some new stuff

how can i set up htaccess to redirect google to those posts?