In this example we are adding a new Text object to our Producer Help - Page(s) design and we have it set to the default Standard Object Type, Fixed Value, and we enter a name into the text area, in this case "Fixed" Now we click on the Concatenate button under the formatting options.
Now we get a new option to select a Standard Object Type, in this case, also a Fixed Value is used but this can be any Standard Object Type available.
Now you see that the Standard Object Type is changed from Fixed Value to Concatenation as indicated with the red square above.
The Concatenations are divided by expandable tabs. When you click on the left down arrow 
it will open the selected one and close the previous opened:
You also see a red vertical line on the left. This indicates the group of Concatenations. There are no limitations to the amount of Concatenations you can make. You can always change your Concatenations in the Producer Help - Designer Properties window at the Content section.