Judges' clerks are court employees who assist judges with the administrative parts of hearings, such as finding the relevant papers and setting the date for the next hearing.
If the judge wishes to communicate with you and your ex (or your representatives) before or after the hearing, those emails will come from the clerk, not the judge.
If a hearing is by phone or video, it is usual for the clerk to make sure everyone is present and properly connected before the judge takes part.
Once the hearing starts, the clerk will usually sit quietly until the judge asks for their help. The clerk is not involved in the judge’s decision making, they are just there to help the judge with court admin.