The installer will automatically run Orchids Plus when the installation completes.
A shortcut is also added to your desktop as well as your start menu. Double-clicking on the "Orchids Plus" shortcut will run the program.
You will need to click "Evaluate" (or "Continue Eval") or "Activate" the software before you can start using the software.
See the licensing / activation / evaluation / trial solutions on this site if you have any questions about activating or evaluating the software.