New tenant, how to prioritize

[Oskar Kuus]

I have a tenant that only have teams free licenses.

I am now looking to upgrade to business basic.
We are about ten users.

We have a domain and mail service at another provider.
But i dont know if i will mess things up if i connect our domain to the tenant before we get license for mail in o365. Or can i use our domain on the tenant and then later when we get the licence migrate mail to office365?

What order to do stuff in?

[#2]

You can verify the domain now, as long as you don't change the MX record (and don't provision any mailboxes for now), nothing will change.