y-axis on time series doesn't show values of metric
Re: y-axis on time series doesn't show values of metric
I think it's likely the date that's the problem. Data Studio has trouble reading dates in the format 1/1/17. Try changing them up so that it reads 20170101, then set the date type in DS as YYYYMMDD instead of YYYYMM.
Once you do that, there will be a date dimension option underneath your data source. Once you add that, it should map better on the line chart. You'll likely want to set up a calculated field in DS so that you can map the line chart by month instead of date.