You can analyze only files that are in your project. If your project is new, add files to the project before running a dependency analysis. See Add Files to the Project.
In the project Views pane, select Dependency Analysis.
If you want to analyze the dependencies of external toolboxes, select Options > Analyze External Toolboxes.
After you run the first dependency analysis of your project, subsequent analyses are incremental updates. However, if you update external toolboxes and want to discover dependency changes in them, you must perform a complete analysis. In this case, turn off Options > Perform Incremental Updates before running the dependency analysis.
To analyze all files in your project, on the Dependency Analysis tab or view, select Analyze.
If you want to analyze specific files, on the Dependency Analysis tab, click Analyze > Select Files to Analyze. In the Dependency Analysis dialog box, select files for analysis, and click Analyze.
In the Simulink® Editor, if an open model, library, or chart belongs to a project, you can find file dependencies. Select File > Project > Find Dependencies. Simulink analyzes the whole project and shows upstream and downstream dependencies for the file.
For next steps, see:
To try a dependency analysis on example files, see Perform Impact Analysis with a Project.