Information of a debugging session is displayed in the dedicated tabs of the Debug tool window, named after the selected run/debug configuration.
For each session, use the Console tab to view the debugger messages and application output, and the Debug tab to monitor threads and frames:
If in course of the debugging session, you need to work with an interactive debugger console, click 
button in the
toolbar of the debugger console. The console becomes interactive: it shows prompt, where you can type commands, execute them, and review results.
