system information & flash storage

Hi,

I am trying to find out what over 50GB of "other" files are on my MacBook. I was trying to install Big Sur but this was rejected as I have too little available space. I've deleted loads of stuff but the "other" has gone from 46GB to over 50GB now.

I can't find where these other files are kept as they are hidden.

Any ideas? I am a basic user so I don't know my way around under the bonnet so to speak.

Thanks in advance for any help offered.