Problem with truck transporting steel?

[EEW]

I am having trouble getting my trucks to load steel at the factory in the first beginner scenario. The truck is the same type that carries lumber, and it appears to be waiting for lumber rather than steel to load. Meanwhile, I'm carting in lots of iron ore and coal, and steel is showing up (in small quantities) but vanishing, never loading onto the truck that is sitting in the same station waiting for it! Do I somehow have to tell it that I want it to load steel rather than lumber? If so, how?

[Steve]

When using Full Load and Unload, hold down the mouse button to select the type of cargo.

[EEW]

Thanks...That worked!