Relative date filtering for arbitrary amounts of time

I want to set a filter for an arbitrary relative time from today such as “last 12 months” or “last 180 days”. Simply typing that text into the calendar doesn’t seem to be working for me, it just picks a date from my data.

I see that there is relate date filtering available but I’m not sure if I’m using it wrong or it’s just limited at the moment.

Make sure that you select the column as Date.