The software has a built-in introduction which will take you through the initial steps, and overall workflow. You can view that introduction at any time by choosing “Introduction” from the help menu.
Running the software in trial mode will prompt you to enter a license key each time you start the application. The message will no longer appear once you have purchased the software.
See also the License & Registration FAQ.
By default, the application is using “safe” settings for audio and display. This includes quite a high audio latency, which you might want to lower.
Visit the Preferences to customize your audio and display settings.