The 90 day reporting doesn't start until they get their first extension on a Non-Imm visa.
When they get the extension, they will get a small paper in their passport that tells them when the first 90 day report is due
You can make an appt online for the ED extension at this website
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Also remember if you don't make an appt, they only give out queues for the ED section until 12.
That section is a nightmare, a friend showed up at 7:30, went in when they opened at 8:30 and got queue 150 something for their ED extension. Their number didn't come up until after the office reopened for lunch at 1PM