OpenBUGS: get a sample from a random variable

Question

I'm working in OpenBugs, and I've defined the next model: $Y\sim {\rm Exp}(\theta)$ so I'm asked to assign different initial distributions to $\theta$: Normal, Gamma and log-normal, to this point everything is fine, the model is initiliazed but I want to get a sample $(Y_{(n)})$ and get an histogram. How can I do this??