To check if your words are a brainwallet.
Load this page:
https://web.archive.org/web/20131031041506/http://brainwallet.org/
turn off internet.
type words,
copy words and address into text file.
repeat for whatever you think should be the right combination (8 words, 8 words plus password, etc)
save text file.
restart computer.
load text file,
check addresses at https://www.blockchain.com/explorer
If you find the address with the bitcoin.
You can start at step 1 to enter the words to get the private key.
copy private key.
You can import the private key into a bitcoin wallet (like electrum, available from https://electrum.org) to access your bitcoin.
if you don't find any bitcoin, it's probably not a brainwallet.
This is not a safe environment to play around with private keys. On an online device or your daily driver you basically can't assess the security status of it. Turning off the internet connection and saving files with private keys and resuming online state later doesn't make anything more secure. This is UNSAFE handling! Should there be some more or less sophisticated malware on the device, it will (potentially) exfiltrate valuable data when the online status resumes.
Don't fool yourself with such unsafe practices!
You either boot a known safe system like a Live Linux or TAILS which both run only in RAM and won't store anything persistantly unless you do it intentionally e.g. on some USB thumbdrive, or you setup a clean spare offline computer which stays offline and which you treat like a cold wallet. The goal is to have safe control that potentially valuable private keys can't be leaked unintentionally.
Too many people have not much clue of computer security and especially safe practices in the context of crypto coin space.