The further processing is explained in full details in my answer on: How to delete files/subfolders in a specific directory at the command prompt in Windows? The Temp directory of the user directory is made the current working directory for cmd.exe processing the batch file if existing at all. That prevents the deletion of the Temp directory ...
The temp folder is not always deleted, even after proper shutdowns, and the space can pile up to large proportions. You don't need to delete the folder itself though, only its content. You can safely select everything, and shift-delete the files to permanently delete the files. It will fail deleting everything and will complain that some files are in use. Just say Ignore for all occurrences ...
I wanted to do disk cleanup myself and found a large folder in %localappdata% called Temp. I wondered if deleting the contents of it won't harm my computer. All I know about "temp" folder...
What are "temp" folders used for in Windows 10? - Super User
Make sure you are indeed in the temp folder, then hit yes. Normally I would say, just shift-delete it, but it appears that IBM stores sensitive userdata in the temp folder. It will try to delete all files, but it will fail on a few files that are currently in use. This is normal. Skip all those files and continue.
The %temp% in the Run command line will show the contents of the logged in user's temp folder. I always recommend deleting as many files as possible in this folder, as they are only temporary files and can safely be deleted.