For the Animator in Server Express, you cannot set a global break condition (i.e. unassociated with a particular statement in the Procedure Division), where execution would stop whenever the value of a data-item changes. This was a feature of earlier releases of MF COBOL, such as Workbench and Object COBOL Developer's Suite, but it's not in Server Express.

Instead, you will have to set a breakpoint on a particular statement, using the If option in the Breakbpoint menu. Execution will break on that statement if/when:

That statement is reached, and the condition is met.