Hi, Kim!
I'd start with Christine's suggestion to check with your Articulate 360 account administrator to confirm if you should have admin rights. If you're interested in learning more about the different roles and permissions within Reach 360, you can check out this article.
To log in, Articulate 360 admins and seatholders can access Reach 360 from their Articulate 360 dashboard or the site URL. Learners can access Reach 360 only via the site URL, using the credentials they established when creating their account. Learners can use Google Authentication to log in as long as their email address matches their login credentials.
I hope this helps!