I have tried the example (USB Communications Device) but it seems no communication via USB (no breakpoint hits on the line VCP_write(“\r\nYou typed “, 12);).
Most likely your device is using a different clock frequency than the device used in the default USB communication sample. Please try locating a sample for your device/board in the ST samples folder and copying the SystemClock_Config() function from it.
Another alternative would be to select “Use STM32CubeMX samples” when creating a new project. This will locate a matching ST sample for your board that should have the correct clock settings specified.
It’s actually a bit more complex. If you are not familiar with the STM32 clock settings, please try using the STM32CubeMX tool to specify them graphically (see this tutorial for details). You can also try contacting Olimex for examples that work with their board.