How can you exclude the /Users/anna/Downloads/ folder from Time Machine backups?
Open Time Machine, choose Preferences from the Time Machine menu, click the Exclusions tab, click the Add (+) button, navigate to the /Users/anna/ Downloads/ folder, and click Submit.
In Finder, control-click the Downloads folder for the anna account, click the Sharing and Permissions disclosure triangle, click the Add (+) button, add anna to the list of users, and set the Time Machine user's access to No Access.
In Terminal, execute the command sudo defaults write/Library/Preferences/com.apple.TimeMachineexcludedFolders -array-add/Users/anna/Downloads.
Open the Time Machine pane of System Preferences, click Options, and add the /Users/anna/Downloads/ folder to the list of excluded items.