The Flipgrid app is only used for learners to access Topics and Groups. Learners can watch videos and record their own all within the free app!
Educators use the mobile browser to manage and add content on their Topics and Groups by going to admin.flipgrid.com. Flipgrid provides a link to the Educator Dashboard within the extended settings of the app.
Are you trying to join the Topic as a learner and record videos? Learn how to use the mobile app for learners.