The Concept Simulator is basically a respondent Simulator. This can be used to determine what choices will be presented to the respondents when your survey is actually deployed. You can use this information to determine either the number of respondents you need to send the survey out to, or the Minimal Choice Count. With QuestionPro, you can use Concept Simulator in Conjoint analysis as shown below:
Go to: Add question » Advanced » Choice models » Conjoint. Conjoint Analysis question type will be added in the survey: