The marking on these capacitors is 103Z. Z refers to the dielectric type. 103 is the capacitance value in picofarads (pF) where this is read as 1,0, followed by three zeros. You may well get capacitors with just "103" as the marking. In the circuit, C1, C3, and C5 are used as D.C. blocking capacitors. These allow the radio signal to go from one stage to the next while not changing the D.C. conditions set up with the resistors. C2 and C4 are used as R.F. emitter bypass capacitors. They allow the radio currents to bypass R1 and R3 which keeps the radio signal gain of those stages as high as possible.
0.01uF =