Adafruit's Pro Trinket is very similar to an Arduino UNO however much smaller. This sketch is useful validating you can successfully program the Pro Trinket.
The Pro Trinket provides facilities to be programmed using either USBTiny or FTDI interfaces.
Be certain to select in the correct configuration in CodeBender based upon both the Pro Trinket model and which programming interface option you are using.
Pro Trinket Configurations: