We just got our 3Doodler today! Here is the initial unboxing, and a test doodle.
You preheat the device and then load the 3mm filament from the top. The two buttons are for slow and fast extrude. And if you hit both at the same time, it will reverse the filament.
When you push the button to extrude, it starts the cooling fan that will cool the extruded filament, then it seems to heat up for a moment before the geared motor pushes the plastic out the extruder nozzle. When you release the button, the extruder retracts a bit, and then the cooling fan stops a little bit after that.
Although it's curved from being on the spool, our 3mm PLA and ABS filament works very nicely with the 3Doodler. (We carry orange, yellow-green, grey, and gold - which were not in the 3Doodler sampler packs that we received.)