Hey @kesslw, welcome to our Community!
There are a few things you can try.
You can join with your existing email, and personal Dropbox account and move your files there. You can always create a new email address, and a brand-new Dropbox account, and ask your team leader to invite this account to join the Team.
Or, (and you'll see this when trying to join the Business Team) you can move your current files to a new personal Dropbox account. You can start a fresh Dropbox account with your business email on your Dropbox team and keep your current files in a personal, unmanaged Dropbox account.
Please note that any team owned folders will be moved to your new work account.
If you have any questions, I'm here to help!