Grouping Forecast Achievement by Month

Grouping Forecast Achievement by Month

Hi all

I have the Forecast setup in CRM and I now want to create a dashboard widget on my manager dashboard to show our achievement against target by month. 

I can't see a way to group by forecast period or by forecast month in the settings for the dashboard. Can anyone assist?


Ultimately I'm after something like a chart with a column per month for our Target and a column per month for the Achievement, so that's two columns for each month. Or it could be a line graph, anything. 

Olly