Your journal is a great place to see what you've done so far, and plan what you're going to do next. You can use it to Save and Load your progress, change your Options, and there's a helpful Map in the back! Press the Start button to open your journal.
The first time you open up your journal it will explain to you what each section is, but if you forget or didn't read all that, this section is for you.
To navigate the tabs use the Left analog stick.
Here you'll find all of your basic pause menu stuff. Options, Load, Save, Credits, and Exit (which quits the game entirely, not just exits the menu).
This tab shows the collectibles for the current area you're in. You can take a closer look at figments with the "Figment Viewer" in this tab.
This page shows you how you're doing in the bigger scheme of things. Also, once you get your Scavenger Hunt List (see Scavenger Hunt section), this is where you can reference it.
This tab shows your current tasks. If you're ever unsure what to do next, check this sectin.
Once you've cracked open a Mental Vault (see items section), you can review those memories here.
This tab has a map of the campgrounds. It marks your position with a red arrow, and the next place you should go is marked with a green cross.