To make Magical work on multiple devices with the same email, you will need to do the following:
The shortcuts on computer #1 will transfer over to any computers that you sign in with. If you add a shortcut on additional computers, all other computers will be automatically updated as long as you are signed into the same account.
If you are looking to have distinct email addresses that share common shortcuts, this is a new feature that will be adding soon! Until then, send us a note at firstname.lastname@example.org and we can give you a quick way to share shortcuts across multiple accounts.