How to set up .gitignore?

Question

git

Hello.
Project structure:
*directory*
*file*
*file*
*file*
_____________________
Directory - folder "vendor", there are a lot of library files.
I need to open 1 folder at the 3rd level deep into the vendor'a, and close the rest for the git.
How to spell it correctly? Is there an option to close the entire vendor except for one directory inside?
Or is it necessary to write 100500 rules for all directories inside the vendor, please tell me.
I read the documentation, I see something like this:
/vendor/*
!/vendor/.../.../"open folder"
Right?
UPD. It worked like this:
/vendor/*
!/vendor/tier1/
/vendor/tier1/*
!/vendor/tier1/tier2/
/vendor/tier1/tier2/*
!/vendor/tier1/tier2/tier3/

Answer 1

True
, only you need to change the order, exceptions are described first

!/vendor/.../.../"открытая папка"
/vendor/*