1)  In Tailor -> Options, set this to 4 characters.  The button next to it is used for how you want to cross reference a RSU T-Shirt Size like "Adult Medium" to a RD 4 character code.  RD stores this as a small code because many want something brief for the Participant ID label.  But, you don't need to do any setup prior to importing participants.  When  you import participants, this cross reference is created automatically.

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2) In Update -> Participants, use the "Imp" button to import participants from RSU.  We'll use these settings to re-import everyone and to use the cross reference above.

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At the end of the "Get Registrations" step, you'll get this prompt -

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RD creates a temporary code for each size imported -

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Which you can change to something meaningful -

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3) After the import, each participant will have a meaningful code.  If you return to Tailor -> Options, you'll see them here.

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