You can download the instruction manual for this machine and many others from the webpage here:
https://www.ifixit.com/Guide/Old+Sewi...

The machine in this video was made in Switzerland in 1977; its serial number is T2096015. It was manufactured to a very high standard and was made to last.
The Elna TSP can do adjustable straight stitch, adjustable reverse stitch (via the stitch length selector), zigzag, buttonholes, and has a number of built-in, practical, decorative stitches, including stretch stitches. Additionally, the machine is arranged for twin needle decorative sewing and the needle position can be changed – left, right or centre - as required.