Start with the right checks.
Storage pressure needs a review of the actual contents. Start with large files you recognize and the Mac’s own storage view, rather than an optimizer advertisement.
What to do next.
Open the Apple menu, System Settings, General, Storage on current macOS versions.
Review the categories and identify large items you own. Ask before removing shared or business application data.
Copy files you need to an approved separate location and open the copies before deleting originals.
Review the Trash before emptying it. Keep unfamiliar Library and system folders intact.
Check the result.
Return to Storage and check the available space. Try the task that originally reported a shortage.
Stop and get help if…
Space disappears again quickly, the largest category is unclear or you cannot establish another copy of important files. A storage plan may be more useful than another round of deletion.