I followed this video Date Comparisons in Analysis Workspace | Adobe Analytics - YouTube
but when right clicking in my workspace, on a metric, I only have "add time period column". Is there a feature or something that has to be turned on?
If you breakdown by time period (day, week, month) this option won't be available.Try removing the time period breakdown and use "Compare Time Periods" option. Hope this is helpful!
do you have "time dimension" (day, week, month) as breakdown (row items)? I think it doesn't work with those dimension...
You may try to drag and drop any time dimension or gradularity onto the "column", then use "create calculated metric" function for the comparison.