E, B, and C are short for Emitter, Base, and Collector. The transistors in that pic are "NPN" (the opposite of PNP, so be sure to buy the right ones). If you look at the symbol for the transistor in this schematic the top wire is the Collector (because it "collects" the source voltage), the one pointing to the left is the Base (the ground, more or less), and the arrow is the Emitter (because it "emits" the amplified/switched voltage that they transistor is there to work with in the first place).
As for the capacitors, they are all listed by value in this schematic. Just buy a huge pack of capacitors with a large selection made for low voltage electronics and you'll be fine. The voltages will say 100V, 200V, whatever, but that's not important as its the maximum voltage rating. As long as its more than they 5 or 12 volts your circuit will use its fine. The important number is the part that says what the capacitance is. On this sort of thing this is measured in micro Farads, and is written as "μF".
"Polarized" can mean different things in different situations but mainly it referrers to something that, for whatever reason, is made to have voltage applied to it in only one direction.