The first section from your original link - "Creating rescue media" - should have the steps needed to create a bootable CD/DVD or USB flash drive.

https://knowledgebase.macrium.com/di...g+rescue+media

What step(s) from the link above did you have issues or questions on? From what I can see, it shouldn't ask you for the backup image until after you have booted from the rescue media and selected Restore.