How do i get MerkleProofUpgradable.sol?

this is a repost because i was unaware this subforum existed

how do i begin using these? i'm doing a ctf right now and i cant even get it compiled
i keep getting

Error: Source "openzeppelin-contracts-upgradeable/contracts/utils/cryptography/MerkleProofUpgradeable.sol" not found:

i followed the instructions on OpenZeppelin/openzeppelin-contracts-upgradeable

and i have searched for that file on my hd and the internet in and can't find it.

i used forge to install it and it's just not there. i don't know what i'm doing wrong

where/how to i get the upgradable.sol files?

this file exists and folks use it but i'm just confused - where does it come from? i can see references to it on github issues ( but not sure what's going wrong. can anyone here help me?

:computer: Environment

Duplicate of Where do i get merkleproofupgradeable.sol?