Right now, eJourn has 3 plugins.
This plugin adds a toolbar just below the menu. It adds quick links to everything in the edit menu (except preferences). And it also adds the ability to go forward and back.
Note: You can go back after switching journals. You will actually be prompted about opening a file from another journal.
This plugin adds a menu to the menubar called "Journals." The menu will have one entry: Create New Journal.
Clicking Create New Journal will bring up a dialog to create a new journal. And you can also switch between these journals via the menu that this plugin adds. All journal titles will be listed out under it.
Also, be careful, do not give two journals the same name! Not only will they be hard to find, one of them will be utterly unusable as you won't be able to open it.
This plugin allows you to, somewhat, use eJourn in conjunction with a command line. See ejourn -h for details.
Some of this is broken and is on the list to fix, but I honestly don't think anyone uses it so it's very low. About the only useful thing you can do from here is export your journal to html.