The VideoLAN Forums

update says

"You will need to manually launch from your temp folder after the download."

what is the temp folder and where is it located. VLC downloaded something. Where is VLC putting the files once they are downloaded?

You shouldn't be seeing that message when installing the latest version which is 3.0.17.4 It only appeared due to a bug in the 3.0.12 and 3.0.13 installer and was fixed in 3.0.16

Your best bet now would be to download the latest version and run it over the top of the version you have now. https://www.videolan.org/

To answer your question about the Temp folder you can open it by going to the Windows Run command and type: %TEMP% and click OK. Alternatively, launch Windows File Explorer and go to C:\Users\Username\AppData\Local\Temp (substitute "Username" with whatever name you log into Windows with).