If you want to change the settings of a specific Journi, just click on the three little dots next to its title. There are several things you can edit:
Just click on the cover to choose a photo which you want to use as a cover photo for your Journi.
By clicking on the title you can add or edit the title of your Journi.
For each of your Journis you can choose between three different privacy setting: public, private and secret.
You can also add followers and collaborators for each Journi in its settings.
You find even more information here!