Philips PM3302 Oscilloscope

Hey folks, I could do with some operational help with my newly 'aquired' oscilloscope.... hehe I was at my local tip last week and found it amongst the tellies and other 'junk'!
When I turned it on it initially suffered from a steady 'ticking' with a glitch appearing on the trace, but I tracked this down to the EHT cable that had become partially detached within the nipple! So that is hopefully sorted...

I just can't work out how to use the digital storage function though, and after playing about am beginning to wonder if this part of the scope is faulty?

Can someone give me any pointers please?

Here is a piccy...

I'm not sure, but the here's the manual for the PM3305. It may be close enough. https://bama.edebris.com/manuals/philips/pm3305/

Thanks, I will check that link out!