Finding the trucks in the practise range

[flying buick]

Use the map, luke.

Really, as you're passing over the highlighted area, just focus on looking down, and you'll see white specks that look like they dont belong there. Those are your targets.

Wait till you have to deal with those vehicles in Stalingrad lol.
I'll tell you right now as a pre-emptive strike on your question; for that specific mission, switch over to realistic to find the targets then bomb them on simulator.