The lever must be pushed to the side a bit, attach the strings, & then they are pulled tight as you push the lever up. There is a small wire loop on (like on a necklace ) to hold the strings.

T Dennis- thanks alot! Is this throw-off design practical? Does it work OK? Is the drum worth getting??

I would say a definite yes, if the throw & butt are all intact. It's not a great system to begin with, & needs to be looked at carefully. (of course the price, & condition are what make it "worthwhile"). Your lucky to find a snare that has the front pop-on strainer cover, most are missing. (remember, many sellers will not know what parts are original, or missing, on these old snares). They also have a large & complex muffler.

So, if the one I'm interested in looks like your pic, it's complete? The muffler is missing the felt pads. Not a biggie... I don't usually muffle my snare drum. Did Sonor use beech shells??

My snare is missing the front cover. Sonor snares/drums were well built, but there is always an engineering weakness on many great drums. The most frequent design weakness is the strainer system. If you find a drum where everything works, then get, it & be aware that it may take some special care. Google "Sonor Museum" to get an extended, detailed examination of all things Sonor.