If your school are moving from Dynamic Learning to Boost, all your teacher accounts will be transferred.
These accounts will sit under the 'Without access' tab in the Admin Hub. Your schools Access Coordinator for Boost, or any approved Teacher Admin, will be able to 'Grant access to the selected':
Granting access to these accounts will also edit their role to 'Teacher Admin', which the default role in Boost:
For more information on adding/editing/deleting teacher accounts please click here.