From Documentation
You can neatly line up components using hbox and vbox. The hbox component is used to create a horizontally oriented box. Each component placed in the hbox will be placed horizontally in a row. On the other hand, the vbox component is used to create a vertically oriented box. Added components will be placed underneath each other in a column.
For example,
<vbox> <button label="Button 1" /> <button label="Button 2" /> <hbox> <button label="Button 3" /> <button label="Button 4" /> </hbox> </vbox>