# Creating a custom POU

You can create a custom Program Organisation Unit in the POU tree.

1. Start editing the real-time application.
2. In the menu bar, click Program.
3. Click the plus icon next to FUNCTION BLOCKS.

5. Identifiers are case insensitive and must begin with a letter or underscore character. Multiple consecutive underscores or trailing underscores are not allowed. Name the Program Organisation Unit uniquely.

6. In the Type listbox, select the type of the Program Organisation Unit.
7. In the Language listbox, select the programming language you want to use.
8. Enter a description.
9. Click Save.

1. The custom Program Organisation Unit is displayed in the POU tree and the catalogue.

Creating a custom POU