Datasheet

Plug in the Trinket, make sure you see the green LED lit (power good) and the red LED pulsing.

Press the button if the red LED is not pulsing, to get into bootloader mode.

Click the Upload button (or select File->Upload)

If everything goes smoothly you should see the following (no red error messages) and of course, the red LED on the

trinket will blink on/off once a second

The Serial Port menu will not show the Trinket, that's normal!