Singer 211 stitch length

I use a Singer 211g to supplement my Sailrite machine and am having difficulty understanding how to change the stitch length on that machine. Does anyone have a good set of instructions that shows how to change the stitch length on that machine? Something with visual aids would be awesome. Thanks.

So, I see that in my haste writing this post, I was not clear about the issue I was experiencing. I knew “how” to adjust the stitch length, but I could not get the machine to adjust. After reading another post on another website, I discovered that the previous owner had tightened the screws on the adjuster eccentric so tight that adjustment was not possible. I backed the two screws out, made my adjustment, and then re-tightened. I did not tighten them to excessive amount this time (snug, but not tight) and now adjustment is simple and easy. I will have to monitor the screws to ensure they don’t walk out under vibration for a while.