As an example, a bias design goes something like this: "Let's see, I'll pin the base at five volts with a resistor divider. The emitter will be 0.6V below that. Then the emitter current will be (5.0 - 0.6) divided by the emitter resistor. The collector current will be essentially the same, so I can pick the collector load resistor to give me an appropriate quiescent point and make sure the output impedance is less than a tenth of the input impedance of the following stage (so I can ignore the latter)."