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 school's Access Coordinator for Boost will be able to login and select those teachers and click '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.