Sprint Board style depends on your selection of Sprint board type that can be Scrum or Kanban. Both boards have designed to equip you better with different features. At the creation of a Sprint, you can select Sprint Board Type but it is editable later as well.

• Open Sprint that you want to change, by selecting Sprint from the main navigation menu.
• In Project drop down, your selected project is selected.
• From Right Navigation Menu, select Settings > Edit Sprint Details > Kanban/Scrum (choose the board you want) and save it.

Changes will be applied and the board layout will be changed accordingly. Learn the difference in Scrum vs Kanban Board.