Gem will automatically pull your Outlook aliases so that you can use them in your sequence.
Outlook lets you have multiple aliases associated with a single account, and you can choose which email address you send email from. Creating aliases can be used in this case to protect your primary email address.
Provisioning Outlook aliases
Ask your IT Administrator to provision a new alias that can be used to send emails from. This guide has more details.
Verify that receiving email works
Make sure that emails sent to this new address end up in your own email inbox. Ask a colleague to email to your newly created alias, and make sure you receive the message.