# Adding a POU to a program

1. Start editing the real-time application.
2. In the menu bar, click Program.
3. In the catalogue, navigate to the Program Organisation Unit (POU) you want to add by browsing the categories or by using the filter.

4. If a Program Organisation Unit written in Function Block Diagram contains multiple networks, the order of execution depends on the last element's position on the worksheet:

   1. From top to bottom.
   2. On the same level from left to right.
5. Drag-and-drop the Program Organisation Unit to the desired position in the worksheet.

Functions and function blocks of the standard library