For doing a manual monogram (by hand, not using embroidery unit) Follow these steps.

1. Put on the "N" foot ( This is your open toe foot, so you can see easier)

2. Select the zig zag stitch (Should be #4, right next to the straight stitch)

3. Hit the stitch adjustment button on the screen ( Lower left)

4. Set the width (Will have a zig zag "/\/\/\/" icon) to whatever size you would like (Usually 4.0mm to7mm)

5. Set the length (will have a line "---------" icon) to a very short setting

You're now setup for a monogram. You might like this video too for using your embroidery unit.
Let me know if you have any more questions,
Chris