You can get predictions from your model in a couple of ways.
One way is to go to the red triangle popup menu for your model and select Save Columns > Save Prediction Formula. This will add a column to your data table that provides predictions for all observations. Adding a new observation and typing in the values will give you a prediction.
The other way (probably easier) is to go to that same red triangle popup and choose Profiler. That will give you an interactive picture of the model. Dragging any of the red lines for the factors will allow you specify the factors and the predictions will be updated on the graph.
As for ROC, that does not seem to be available in PLS-DA. I guess it is a platform designed for more than a binary response. I'm not sure how to get it unless you wanted to build it yourself.
Dan Obermiller