Windows 10: Can't Create System Image on External Hard Drive

Recently my ssd had started failing so I replaced it with 2 new ones. I'm trying to transfer the os from the old ssd to the new one. I read online that I need to make a system repair disc and a system image. I was able to create the system repair disc with no issues however I am unable to creat

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Capacity of external system image hard drive

In creating a system image, what capacity hard drive the backup must be saved on?
Should the capacity of the external hard drive equal or exceed that of the source drive?

In the event of a system crash, how is the operating system restored with the system image created?

 

System image on an external hard drive in Windows 10?

How can I create a System image on an external hard drive in Windows 10?

 

Using system Image external hard drive or system repair disc.

Could some one give me step by step instructions on how to use either a system repair disc or a system image on a external hard drive. My computer has been acting up, losing files, documents, music and pictures, right clicking on start button will not produce context menu, and clicking on edge does not open it. I created a system image and a repair disc a month or so ago, but do not know how to use them to see if my problems could be fixed. Also, can't I just reinstall windows? How do I do that without a CD. None came with the computer; Thanks for any help.