The Journal window shows you your Objectives, information about the inn and your character, and allows you to enter the Help and Tips option. You can choose the Journal from the menu on the right side of the screen.
The first tab of the Journal shows Objectives. They may be related to both the story or just gameplay in general. By selecting one you can see its description, tasks related to it, and a reward for its completion. Once its completed, you will have to click the Claim button, to receive the reward. It may be Fame, money, a new recipe, etc.
By choosing the eye icon, Watch, you will add the given Objective to the list of Tasks you can see at the upper-left corner of the screen.
Inn and upgrades
The second tab shows information on the inn and the innkeeper. On the left side you can change the name of the inn, as well as see the expectations and possible behaviours of your guests, and a level of fame that unlocks those. Below you can see how many satisfied guests you need for a new fame point.
The right side of the window shows you all the possible upgrades you can get for your inn. In the top right corner you can see how many points you have available to spend (each fame point equals a point to spend here).
You can only unlock a skill/perk bordering one you already have. By pressing an icon with a left mouse button you can learn what it does.
Help and Tips
The last tab of the Journal shows you help and tips which may be useful during the game.