The Spectre models for the OnSemi/AMI C5 0.5µm CMOS process are located at
/home/pdks/ncsu-cdk-1.6.0.beta/models/spectre/standalone
Select the models ami06N.m and ami06P.m in the ADE window models setup, before you attempt to run the simulation when designing with C5 process.
The Spectre corner models for the C5 process are located at
/home/pdks/ncsu-cdk-1.6.0.beta/models/spectre/
You should see directories for typical (tt), fast-slow (fs), slow-fast (sf), slow-slow (ss), fast-fast (ff) corners. Choose the desired folder and select the models ami06N.m and ami06P.m in the ADE window models setup.