RegEx Redirects for Legacy URLs
Here's the regex I think you'll need:


\/teachings\/tag\/\d+\/(\w+)\/? → \/teachings\/topics\/$1
\/teachings\/series\/\d+\/(\w+)\/? → \/teachings\/series\/$1


A couple explanations:


\/ is an escaped / character
\d+ means one or more digit (0-9)
\w+ means one or more alphanumeric/underscore character (A-Z, a-z, 0-9, _)
surrounding something in parentheses makes it a capturing group, which can then be referenced when you're doing the "replace"


So in our regex we're matching the current url structures, capturing the slug, and then using that in the new url structures. Hopefully that helps!