To make Magical work on multiple devices with the same email, you will need to do the following:
Step 1: Register with Magical on computer #1
Step 2: On computer #2, and others, login with the same that you registered with on computer #1
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. Note, it may take up to 6 hours for data to sync across devices. You can open https://www.getmagical.com/help to automatically trigger the sync and avoid the wait.
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.