Firstly you need to attach an external storage device to save the backup to, for example an external hard drive
Once plugged in you should see the drive is connected to your MacBook
Click on the Apple logo in the very top left corner of the screen
Click “System Preferences”
Click on “Time Machine” to open the backup settings
Click “Select Backup Disk…” to choose where to backup the device to
Select the drive where to store the backup, in this example our external drive is called “External Drive”, click “Use Disk”
The device will now automatically perform a backup of the device. Depending on the size of your storage this may time a long time, to prevent errors leave the device turned on and plugged into the mains.
The backup is now complete, the “Latest Backup” should now show as “Today”

