You may have a PDF file containing merged cells and you want to carry over that merged cell formatting to your output.

Creating a basic layout will either cut the data in the merged cells into separate columns, or it will push it all into a single column if you have the "Merge cells with overflowing text" option selected.

The first thing you want to do is selected the cells in each row that need to be merged, then right-click and select "Merge" to set the layout.

This will push them all into the first column.

You'll notice that, if you convert your file now, your merged cells show up in the first column, just like in the preview.

However, that's not how you want it to look in your output. 

Open your Options and go to the Conversion tab.
Place a checkmark in the box labelled "Merge cells to match layout".
Click OK.

Now, when you convert your file, the output contains the merged cells with the proper layout.