Pretty basic, did I mention how to make a simple periscope out of a couple of small mirrors, a box and placing them along the right angles. What you do with it after that is “nonemebeeswax” (none of my business), but I can imagine it might come in handy if you need to see over or around something without being seen (sneaky little hobbitses).
Oh wait, the thing is Beloveds, that please you need to be aware that you might see something yer shouldnee! Privacy is paramount! So don’t take liberties, let people get on with their private lives, etc… There’s laws in place and it’s best to keep that in mind, having said all that it could be fun in a public place, where the UK law says we’re allowed to film what is going on in the street. This freedom doesn’t apply to private property. So, what you waiting for?