Somehow this got posted in the Off Topic area, stupid iPhone(I hate technology)

I'm getting beat by the trip counter and it's making me feel real stupid right now so I'll ask y'all. I can't get my trip odometer to work. I click the button once and it goes from the odometer to the trip odometer, I click it again and it resets but it never raises from 0.0mi no matter how much I ride. From there I can't even get it to go back to the odometer, it just stays at 0.0mi. I'll forget about it and then when I gas up I'll look at it after I start it and it will have my trip mileage on it. If I touch the button to either just click it or hold it, it will reset and then just stay at 0.0mi.

Can someone break this down Barney style and tell me how to properly work this dang thing?