If you want to install a bootable backup, hold down the Option key while your Mac is restarting and select the clone from your external hard drive in your partitioned hard drive. Your Mac will restore the cloned backup and then restart once it is finished. You're Mac will boot into macOS Utilities.
While the startup disc is waking up, hold down the Command and R keys simultaneously.Note: Because you have to enter Recovery mode on your Mac, I suggest printing out these instructions or switching to another device to read them. If you clone your Mac using a cloning program like Super Duper or Carbon Copy Cloner, you can restore your entire hard drive from a backup, and even create a bootable installer. How to restore your Mac from a local backup
