Capacitor values are given as a combination of numbers and letters, where the `N' stands for `nF' or nano-farad. In the same fashion, a `P' would mean `pF', or pico-farad.
While the range of letters one might use is longer, you'll mostly encounter:

P (pico) 10 to the -12
N (nano) 10 to the -9
uF (micro) 10 to the -6
mF (milli) 10 to the -3

Continuing for resistors:

E (ohms)
K (kilo) 10 to the 3
M (mega) 10 to the 6

When appropriate, a letter can take the place of a decimal point. `2M2' means 2.2 mega-ohms, 2200000 ohms.

Note that on any real capacitor, you are unlikely to read something as straightforward as `100N' or even `100nF'. For reasons obscure to me, it might be `100nS', or, somewhat less obscure, `104' (meaning 10 with 4 zeroes behind). Or, again for reasons beyond my understanding, you may unable to read anything at all because the lettering is incredibly tiny and in low-contrast colors...

Fortunately, many quite affordable multi-meters are capable of measuring small capacitors.