OK, NC: now I understand what you are looking for.
Forgive all the detail in what follows, but I just want to be sure we have a good conceptual "handshake".
When I use the phone, my most general usage is as follows: I pick up the speaker, wait for the dial tone, dial, receive a "calling" tone, receive the answer from the other end, talk, and finish by hanging up. This is the most general usage (nice way of putting it: "happy path"), albeit the fact that in practice there are innumerable variations.
The particular executions or possibilities of a use case are formally called a "scenarios" in UML (no pedantry intended here); these are instances of use cases.
If you double click on your use case in an EA diagram, you can go to the Scenarios tab. This is where you can document the basic and alternate paths. (Since you are going to detail this Scenario in another diagram, you don't need to put much detail here; just give a name to this sequence of events, and choose Basic Path in the Type field).
You can do the same for your other scenarios (your alternate paths, that is), except that you will select Alternate in the Type field.
If you have exceptions, they should be documented in another use case, that should be linked by an <<extend>> relationship to your most general use case.
All of the above is important, because it will help you with your question, and it will also explain what the other forum members are trying to explain.
Now: once you have defined your scenarios, insert a note in your diagram (third icon from left in your tools menu, just underneath the little diskette icon). Link this note to your use case with a note link (I'm correcting Farfetch as well as a previous posting by myself on this one...), which you can obtain in the first item (the one with the arrow) in your tools menu.
Right click in the note link and choose "Link this note to element feature" (as Jason suggests). In Feature type choose Scenario, and click on the first scenario. The name and text associated with the scenario will automatically appear in your note.
From the Worspace (your project tree) now drag the icon diagram that corresponds to the scenario into the note. Voila!
You can now create notes and associate diagrams for your other scenarios.
Hope this is what you were looking for.
Jaime Gonzalez