Electronic – Manuals for oscilloscope wanted

IMHO for its low price, the DSO Nano is actually a good first-time scope. As others have mentioned, you will have problems with showing anything faster than 100-250KHz coherently, but this is pretty high for quite a lot of uses. Yes, you won't be able to see system clocks or PWMs with it, but in my experience a scope is more useful for analog signals, and as long as they don't rise and fall too quickly, you'll be fine with the DSO Nano.

Once you get more money and become more serious about the projects, you should invest in a 2nd hand scope, something real with at least 100MHz bandwidth.

I imagine the 10, 20 and 50V markings are for when the probe is set to 10x. The dial should have two bands to correspond to 1x and 10x settings.

I have an old tek scope which does this - the highest you can turn to for 1x is 5V/div.

I just googled for a picture of the 465b and it looks like this is the case - notice there are two bands on each knob. On the bottom knob you can see one is at 1V/div and one is at 10V/div, which would correspond with 1x or 10x setting:

EDIT - I have added arrows pointing to the bands to clarify things.