Goals tell SOLIDWORKS what data you actually care about. Without goals, the solver doesn't know when to stop "iterating."

Tip: Check "Exclude cavities without flow" to save solve time.

Pick your fluid (Air, Water, Steam, etc.) from the Engineering Database.

The mesh breaks your model into small cells (voxels). In the 2012 version, the slider is the best place to start. Level 3 or 4: Good for initial runs.

If your flow is circling back on an outlet, move the lid further away using a "dummy" extension pipe.

Use the Check tool under the Flow Simulation menu to verify the fluid volume is detectable. The Wizard: Your Setup Guide