If you do not wish to use the pre-bundled software, delete it. You can use your new external HDD straight away.
You can create a System Image from Windows, without additional software.
Open Services (Run > services.msc) and validate that File History Service is running.
Search "create a system image" or "file history", look for System Image Backup.
Select the destination (external HDD).
Click on Next and choose C:\ and EFI System Partition (if visible).
To confirm, click Next and then Start Backup.
From your video, you have no partitions set-up to separate your OS from Documents/Personal files.
If you are able to (and experienced enough), you can partition your internal HDD to 2 partitions; one for C:\ (OS and Program Files etc) and one for D:\ (personal files, downloads etc).
Then when you create a system image backup, you can backup the OS without needing over 200GB of space. The OS itself it usually less than 30GB.
Your files can also be backed up, but independent of the Operating System.