Hi ,
1)First select an appropriate transistor.
2)Design bias network by looking its datasheet.
3)Make loadpull simulation that is under the design guide menu.
4)Then select the load reflection coefficent that gives the power you want.
5)Then realize this load reflection coefficent on the circuit then use harmonic balance analysis to calculate Input Resistance of the device.
6)Design input and output matching circuit with respect to your input and output reflection coefficents then simulate the complete circuit
Thats all,
Alp