Constants are data sources with a fixed value. Their value is not calculated while a process is running, but is defined by the user when creating a data flow.
Add constants to a data flow.
Procedure
Activate the Variables and constants bar.
Activate the Constants tab.
Click the relevant constant and hold down the mouse button. Drag the constant to the modeling area of the data flow and release the mouse button.
You have placed a constant.
Now model the connections and enter the corresponding value for the constant.
You have modeled a constant.