To get to the budget tool, you can select "Budget" from your dashboard. 

Up at the top, you have the option to Export, Reset, Print, or Highlight items on your budget manager.

Below those 4 options, you have a progress bar to show you how much you've spent and what is remaining in your budget. 

To add a new item to your budget, you can click the "Add item" button in the top right corner. 

Go here to learn more about adding items to your budget manager.