I need help with a 4 step buttonhole process – my manua Sewing Machines Parts and Sales in Los Angeles

I have a Necchi FA16 and I can’t find the manual anywhere in my house, or anywhere online. There’s a 4 step buttonhole, and I believe I need to adjust the stitch length or width with each step of the process, but I have been experimenting with different combinations of things for hours and not coming up with any reliable answers.

Can someone help me work this out?