I have been sewing for decades and I still have a little chart to check when I have thread problems. I printed out the little stick man chart from Superior Thread and keep it by my machine. I also made myself a little cardboard chart that says ....to reduce upper thread tension dial the number smaller...to increase upper thread tension dial the number bigger. Below that I printed for bobbin adjustments turn the tiny screw ....tighty-righty or lefty-loosey I keep it in the drawer of my accessories box that came with my Bernina.