Adjusting Ohlins coilovers??

I have some old school…im guessing? ohlins coilovers. I was going to give them to my buddy to run on his R32, but does anyone here know how to adjust the height of them? Both have grooves on them, it looks like you might be able to lower them to a lower groove, but I don’t know. Nothing seems to want to move…whether its because they are old or because I’m doing it wrong I don’t know.

thanks