To install the simulator plug-in do the following:
1- Check first if you have installed the system extension “Mixed Simulation”
2- If the “Mixed Simulation” extension has not yet been installed, please go to the “Purchased” tab and install it. In case the extension does not appear in the “Purchased” tab, check Preferences ► System ► Installation to make sure the “Global installation service” radio button is selected, and try again.
3- Once the “Mixed Simulation” extension is installed, when a schematic circuit is open within in a PCB project, the Design ► Simulate Mixed Sim choice should be available.
Keep in mind that to simulate an electronic design successfully, all circuit components must be ready for simulation, this means that each one must have a linked simulation model defined. Just as a symbol must be defined for a component, a simulation model for that component must be acquired and then linked, so that component is ready for simulation.