The Epson EcoTank ET-2876 does not have an automatic duplex function for double-sided printing. This means that you have to turn the pages manually to print on both sides. Automatic double-sided printing is not supported by this model.
However, you can manually print double-sided by turning the paper over yourself after printing the first page and loading it again. Epson offers instructions and settings in the printer driver to make manual duplex printing easier.