phew im glad someone said to try the old phone your phone in a cage trick as a test
...used to do it all the time in physics
only decent test really, unless you wanna put a pet in there and electrocute it violently xD
but for real though faraday cages are really easy to make and work in a very simple way, all they are is a metal cage pretty much, they simply offer electricity a path of least resistance so instead of going through you, it'll go through metal, simples
although i'd do a fair amount of reading on it, for instance i just read this little snippet
"they shield the interior from external electromagnetic radiation if the conductor is thick enough and any holes are significantly smaller than the wavelength of the radiation."
which if you think about it changes the whole approach to a faraday cage for protecting electronic devices from a solar flare or a man made emp burst
....ill probably toddle off and do some calculations about it and see what wavelengths are probable from each electromagnetic event
anyway i'd research up on it and think about exactly what you want the faraday cage for
if you need more help i can try and find some how to guides