The Toolbar contains the basic block display settings. More settings in the Inspector(Sidebar) panel
Block Alignment Tool
Align Center (Default)
The block will be centered relative to neighboring blocks. And it will have the width of the theme content area.
Wide Align
The block will have the width of the theme you are using. Differs from theme to theme, usually 1140-1200px
Full Width
The block will have a width equal to the width of the browser.
Grid layout
Cols number
Number of columns in the grid Block. The minimum is 1, and the maximum is 12.
Rows number
Number of rows in the grid Block. From 1 to 12.