My iMac Desktop has "died"

[Slydude]

Here's a decent overview of the process you will use to recover your information. When you boot the new computer you should bet given the Migration Assistant option before you create a user account. Run Migration Assistant before creating user accounts. If you create a new account first it will lead to permissions errors when you try to access your old files.

https://support.apple.com/en-us/102613?displayMode=headless