Leave no port behind
Make sure there are no unconnected ports before simulating.
At least 1 frequency source must be present
The spectrum view will be very boring without at least one frequency source.
Start with behavioral models
In the early design stage one might find it beneficial to start with behavioral models rather than X-MWblocks. Behavioral models don’t have real world frequency limitations and behavioral models enhance system architecture analysis by propagating constituent signal path and frequency equation information. Once a reasonable circuit topology is realized with behavioral models then it is straightforward to begin substituting real world X-MWblocks, which are based on either non-linear X-Parameter or linear S-Parameter models.
Start simple and incrementally add complexity
Add only one or two parts at a time and verify that input and output signals are operating withing each component’s envelope before adding more parts to the schematic.