Which organizational unit should I use to install Bluebook?

Chromebooks managed in the Google Admin console are grouped into hierarchical organizational units (OUs), making it possible to install apps and customize settings on a group of devices. 

You’ll use an OU to install Bluebook on testing devices. You can choose one that includes any device your students might use on test day or, if necessary, an OU that includes only a subset of testing devices. 

Students who test with accommodations need to use the Chromebook floating accessibility menu. To limit the availability of that feature, apply the setting to particular testing devices by assigning them to a separate OU.