As ajlittoz already indicated, there are two ways to create multiple column layout.
-
By page style
This allows for consistent column layout across your document, but forces columns for entire page content.
-
By section
This evades the style system, but allows for multiple column setups down a page.
The Format - Columns menu item will default to altering section columns if invoked within a section, and altering page style otherwise. You can change from default behavior inside the columns dialog.
Alas, the section and column settings cannot be part of a paragraph style, so you need to manually alternate between single column headings and multiple column content sections when that is what you need.
Note (as also already mentioned) that Word sections and Writer sections are somewhat different creatures, and Word does not support the concept of page styles (only changing page layout divided into sections). If your document has somehow visited Microsoft Word context (saved as Word doc, or edited in Word), it is highly likely that rogue sections and/or page styles have been created. Those can cause erratic behavior.
Ajlittoz lays your options out in proper detail. Note that frame content does not act on page context flow (only on word wrap where areas overlap), so I instead prefer the singe column page style with multiple column sections inserted.