Attach the external drive if it contains the backup to be used for recovery and make sure that the drive is powered on

Insert your Acronis Recovery Boot CD / DVD or USB stick and restart your computer to boot from this device.  If the computer does not start from the recovery media, Refer to Change Boot Order in BIOS or UEFI BIOS to Boot from CD/DVD

The first Acronis Recovery menu that normally comes up asks you what you want to start from, select Acronis

From the main Acronis True Image 2018 screen, under Recover select My Disks

Select the system disk or partition backup to be used for recovery.  When the backup is not displayed, click Browse and specify path to the backup manually.

Select Recover whole disks and partitions at the Recovery method step

Select the disk(s) or partition(s) on the What to recover screen. System partition is usually named C. If the system partition has a different letter, select the partition using the Flags column. It must have the Pri, Act flags. If you have the System Reserved partition, select it, too.  Then click Next to continue.

Review the Destination of Disk 1 and click Next if they are correct. Otherwise, change the settings as required before clicking Next. Changing the settings will be needed when recovering to the new hard disk of a different capacity.

Carefully read the summary of operations at the Finish step. If you have not resized the partition, the sizes in the Deleting partition and Recovering partition items must match. Having checked the summary click Proceed.

When the operation finishes, exit the standalone version of Acronis True Image 2018, remove the rescue media and boot from the recovered system partition.