How to write a Rewrite rule correctly?

Question

URL Handling

There are addresses of categories like
site/catalog/ventilation/aeropak-sn/
site/catalog/heating/elektrokonvektory/
site/catalog/electricfire/seriya-optimyst/
And addresses of goods like
site/catalog/ventilation/aeropak-sn/1066-pritochna ya -ustanovka-selenga-fko/
After changing the CNC, the category URLs look the same
And the product URLs have become
site/catalog/ventilation/product/1066-pritochnaya-ustanovka-selenga-fko/
Rewrite rule is required to redirect from old URLs to new ones .
From old
site/catalog/ventilation/aeropak-sn/1066-pritochna ya-ustanovka-selenga-fko/
To new
site/catalog/ventilation/product/1066-pritochnaya-ustanovka-selenga-fko/
Where aeropak-sn can be anything else.
Thank you.