It's located in the central display in the IP, cycle to it just like you do for MPG, avg. speed, etc.

You tip either up or down (can't remember) on the rocker switch to start another lap.

At the end of the lap, you can scroll through laps, see average time, best/worst,etc.

Here's a link to a couple of laps at our short lead event 2 weeks ago, you can see the driver hit the timer at pit in.

http://www.cartv.com/content/research/vir/index.cfm/Action/Media/media/video/MAKE_VCH/Audi/MODEL_VCH/RS4/?vid=r_0198