Help with redirect

I have an old site and a new site. I exported/imported about 500 posts of a custom post type from my old site into the new site. The old site used this structure: https://domain.com/blog/catname/this-is-the-post and the new site uses this: https://domain.com/catname/this-is-the-post – I want to make sure that no links are broken. How do I set up a redirect so that if someone tries to visit an old url with /blog/ in it they are redirected to that post without /blog/ in it?
Thank you for any help!