Multipul day entries

This is from the help doc

You can add multiple entries to a single day by using different journals (one named "Work", the other "Family"), separating your entries with different titles (=== Work ===, === Family ===) and using horizontal separator lines (20 "="s).

What does it actually mean?

The way I read it is -
if you have few journals (in rednotebook folder - each journal has its own folder)

and you add
20x= (separator)

and you add
===Name of journal===
with entry of data here

Then
The entry will be added automatically to the journal

But this is not the case.
So what does it mean - you can add multiple entries to a single day?

thank you