To use columns on a page, you need to first define a vertical "section" on the page using the section macro. You can then insert one or more columns into that section using the column macro.
Note that this is different from the page layout in the editor!
Add Section To The Page
Edit the page
Select Insert more content from the toolbar
Select Other macros
Search for "Section"
Select the Section macro
The screen for the section macro will now appear. You can elect to add a border to the section and any columns within it by checking the Show border box.
Add Columns To The Section
Select Insert more content on the toolbar while your cursor is positioned inside the section element on the page
Select Other macros
Search for "Column"
Select the Column macro
Set the width of column by using percentage of the screen width or a fixed size in pixels
You can add text inside the column element that now appears on the page. All content within a section must be inside a column macro! Content cannot exist inside the Section macro outside of a Column macro.
When you add more columns to the same section, be sure to position your cursor inside the section element but outside the previous column element (otherwise, you will nest the new column inside the existing column). Here is the edit view of a page with three columns defined: