Format x-axis quarterly

I've tried to add a "Quarters" series with the 2 columns shown at right in the spreadsheet, but I can't get there.

What did you try after adding this "dummy series"? Here's what I would have expected:

1) Select the newly added dummy series, right click, change chart type, change to column or line chart.
2) Add secondary horizontal axis (assuming Excel automatically adds secondary vertical axis after step 1, if not, you may want to add both the secondary horizontal and vertical axes).
3) Format secondary horizontal axis.
3a) Make sure that it is a date axis
3b) Give it the desired min/max/major/minor units.
4) Format primary horizontal axis so that the min and max values match the secondary horizontal axis values.
5) Hide the primary horizontal axis and secondary vertical axis, if desired.

Perhaps more explanation about what you find confusing or what doesn't make sense. Overall, the new chart makes some sense, though there were some mistakes.

First mistake is that somehow in the process of adding the dummy series, you replaced all of the category axis data for all of the data series. Working from this last example, go through each bar chart series and drag/edit so that the category axis data for each bar chart series is back to C5:C12. This will bring back the category labels along the primary vertical axis.

The main thing that "confuses" me a little is having both horizontal axes at the top of the chart. I would format one of the vertical axes and format it so that the corresponding horizontal axis crosses at the bottom of the chart (if you format the primary vertical axis, select "horizontal axis crosses at maximum category". If you format the secondary vertical axis, select "horizontal crosses at automatic").

Other than that, it looks exactly like what I would expect that this stage of the process. You can proceed to hide the extraneous elements (extra axes and dummy series), and it should be close to what you are looking for.