In the upper right corner I think it should say edit your profile here...
If you go to...
'Theme' is your background.
'Content' is your panels.
You can edit the title of the panels and the content of them by clicking on 'Edit' in each one.
'Caption' gives you speech bubbles.
'Picture' gives you, as it implies, the option of adding pictures.
'Text' is just random text that you can use coding to edit.