Lay the groundwork for is an expression that means to prepare the foundation for something. It is often used in business and politics to refer to the process of setting up a plan or strategy for a project or goal. The two crossword solutions, INSTITUTE and SOW, are related to this expression. INSTITUTE means to set up or establish something, while SOW means to plant or spread something. Therefore, the two words together can be interpreted as meaning to set up and spread the foundation for something.