ADS error： can't get item definition for TSMC_CM018RF_NMOS_RF

when i am simulating the circuit? lecture1_intro.dsn i am getting this error
can't get item definition for TSMC_CM018RF_NMOS_RF.
how can i rectify this problem

This is related to PDK. Place a PDK library component in the design.

i am not getting how to include this Packaged Design Kit can u explain in detail manner

I gone through the document.
PDK is process Design Kit which is TSMC RF CMOS 0.18um in this case.
When you install a PDK a palet will be created in your schematic.
Go to this palet and select the component that you interest in simulation.
These components will have wither 1 or 3 or multiple pins based on the ports avalable.
These components can not be simulated unless the model is available for the simulator.
The PDK developer will use all the models in a library and is available in a component. this component will have no ports.
Place the component namely "TSMC RF CMOS 0.18um" from the palet and try. I am sure that this time it will simulate.

When you install a PDK a palet .
it is available with ADS software itself. otherwise we have to install somthing extra?
it is extra component where from i will get this one.

This is PDK only. I mean there is no process model like "TSMC RF CMOS 0.18um" by default.
You can check it by this procedure given below.
Go to main of ADS project containing the drop down menu namely design kit.
Go to list design kit.
You will find the PDK here if it is not found means you need to install this PDK.

This is PDK only. I mean there is no process model like "TSMC RF CMOS 0.18um" by default.
You can check it by this procedure given below.
Go to main of ADS project containing the drop down menu namely design kit.
Go to list design kit.
You will find the PDK here if it is not found means you need to install this PDK.