Top right buttons from left to right:

Selecting the down-arrow button enables Drill Mode and allows you to drill down one field at a time. This allows us to select a visual element such as the "Non-Property Taxes" data bar and inspect the data within that field.
The Filter button when enabled displays whether there is a filter currently being applied to the visualization. If there is a filter applied it will display on which fields.
The last button is Focus Mode which removes the surrounding panes. this provides a larger view while allowing the user to still interact with the visualization.

Top left buttons from left to right:

Selecting the up-arrow button will return the visual to the previous hierarchy level after a drill down.
The button with two down-arrows allows you to drill down all fields at once. Unlike drilling down one field at a time, this button will go to the next level in the hierarchy for all fields.
The forked arrows expands all the fields at once in the current view. It will add another hierarchy level to the current view rather than drilling down. This button is most useful when interacting with a table, matrix, or tree map.