Why can't I make visualizations by date?

Using web. Newb. Uploaded data to track retention numbers, i.e., how many customers did we gain over time. Want to make a line graph showing how each region changed over time, per month in a dossier. Uploaded an Excel spreadsheet with the region names in Column A2 through A5, and monthly totals showing in cells B2 - M5, each month is in a column, each region is a row. 4 regions, 4 rows, 12 columns of data. When I make visualizations I can show totals by region, but I can't put each month on the bottom axis to show each region by month over time. The month columns upload as metrics and the regions as one attribute. No matter what I do, I cannot make a line graph with the regions on the y axis and the months on the x axis which plots the totals for each month on a line for each region. Any assistance would be appreciated.