brownactive,
You are correct that there is no traditional needle. your gauge on the left should be the tachometer w/ fuel gauge on the bottom. With a full tank you would have eight bars showing. I believe each bar represents 1/8th of a tank of fuel. a bar will disappear each time you have used an 1/8th of a tank of fuel. I personally like to use the estimated mileage range to know how far I can still drive.
One bit of trivial information. There are two different fuel gauges available in the TB's. Higher end models get a little sportier look