How do I sew cylindrical pieces on the XG4099-001?

Slide the flat bed attachment to the left to release it, then slide the part you wish to sew onto the arm and sew from the top. When you are finished with free-arm sewing, install the flat bed attachment back in its original position. (Page 1)

From the official Brother XG4099-001 Computerized Sewing Machine manual, page 1

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