Glossary of terms and icons

Classroom Overview --> Classroom Explorer A separate app window where you can load Classroom classes, users, rosters, and assignment data for all classes on your domain. Learn more.
Job list The list of your sync jobs, where you can view what state each job is in, run sync analysis, and initiate the review and staging of sync actions. Learn more.
Roster exceptions A global list of individual users and email patterns that will not be added and/or removed from a Classroom class during sync.  Learn more.
Class exceptions A global list of individual classes that will be excluded from sync jobs.  Class exceptions are convenient because they can be saved on the fly during the review of potential matches, but they should be used sparing.  Where a large number of classes need to be excluded from a sync, job scope roles should be used instead.  Learn more.

When reviewing a

sync analysis

A sync analysis compares the SIS classes and rosters within a job to the current state in Google Classroom and makes recommendations.  The outputs of a sync analysis are used to review, stage, and commit actions in Classroom.  During sync analysis, you can perform several distinct action types.
   New class to be created  An invitation to teach a Classroom class (a.k.a. a "PROVISIONED" class) will be created if this action is committed.  This invitation will be visible in the Teacher's Classroom home screen, however it will not be visible to students until the teacher clicks "Accept" and the class becomes "ACTIVE."   If the teacher chooses to click "Decline" on the class, the class will enter the "DECLINED" state. 
Class to be updated If this action is committed, a change will occur to either the roster or a field within Classroom, depending on your job settings.  The specific changes to be made can be previewed from within the sync analysis interface.
Class exception to be saved  If committed, this action will add the class to the class exceptions list.  No changes will be made to Classroom for this class during this or future syncs.
Link to existing class If the analysis detects candidate matches in Classroom, you have the opportunity to establish a link to the existing class, which will ensure roster syncs for that class going forward.  Linking a class may also add/remove students during the sync, if there are differences between the teacher's current roster and that in Classroom.
Class to be excluded for this sync This option is available when reviewing detected candidate matching classes in Classroom, and can be useful if not enough information is on hand to make a decision, but you want the option to re-evaluate in a later analysis.