You can't assign based on post count - you have to assign them to each user individually.
Control panel -> Members -> View/Edit Member Records
Enter the user number and hit submit.
When the results come up, click on the user name.
You can assign a title using the resulting new window.
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Charles Capps
Programmer, Infopop Corporation
Please do not contact me privately for support - post on the board or open a support ticket instead!