How do you apply a fashion disc in a singer 306k?

Undo the large silver wheel on the upper front of the machine. The fashion disc locates on to a small pin with the pattern ( on the disc ) visible. Replace silver wheel - set width of zig-zag, and stitch length, and sew. If the stitching pattern created by the fashion disc is asymmetrical, fitting the disc upside ( pattern hidden ) reverses the stitching. 20+ fashion discs were made by Singer ! A DISC MUST BE ON THE MACHINE AT ALL TIMES, FOR STRAIGHT STITCHING