Pressure washer

[Oxo01]

Didn't know where to post this so sorry if wrong
I bought a small P/washer from Aldi it got and still has great reviews.
it said a quick coupling connector was not included
I have loads of hose connectors some universal but when I connect hose to machine the hose won't stay in place so water everywhere. Others won't fit, so I have bought a new type and it does not fit still. Can't keep buying loads to try.
Anyone got a ferrex P/W
from Aldi ? if so what do I need and size if apicable.
pictures would be great
I had it a week sitting in my lounge and will have to send it back if no joy so any help appreciated.