The template will automatically replace non-numeric data with zeros so that the regression analysis will run. Regression cannot be run where values are missing for independent variables and there are two possible solutions:
Fill missing values with the last known value from before under the assumptions that the series has not changed since the last observation.
Truncate the data to include only observations where data is available for all variables. This can be accomplished with a filter and Go to special > Visible cells only in Excel.