By default, Blocs does most of the layout for you by ensuring that content fits precisely within the columns in which it is placed. As such, there is little need to set widths of anything manually. However, if you really do need to have precise widths of elements in your page, you will have to set up custom classes for each element and then use the metrics tab to adjust things such as height, width, margins and padding. When using this feature, the sizes will be displayed on the screen. By using the slider option to make adjustments, you will be able to align elements visually, The screenshot below shows how it works.