HOWTO |Do a basic back up in Time Machine
1 Sort out your storage
Connect a large external drive to your Mac (the larger the better; buy the highest capacity you can afford). If it’s not formatted for the Mac, open Disk Utility, select the drive in the sidebar, click the Erase tab, select Mac OS Extended ‘(Case Sensitive, Journaled)’, then click the Erase button.
2 Decide on directories
Open System Preferences, click Time Machine, then click Options... Click the ‘+’ button adding your internal storage. You can include virtualised operating systems here, which create large files that change frequently. Use the VM’s snapshots tool to back these up.
3 Safety vs Battery life
If you’re using a notebook, decide whether you want to back up on battery or just when using mains power, bearing in mind that you need to balance file security with battery performance. Click Save to store your settings and step back to the main Time Machine preference pane.