How to make Eagle package with dual row surface mount tails?
The PDF you linked to clearly shows SMD pads on the same side of the board:



In Eagle, in the package for that part, place a SMD pad where each pin touches the board.  Usually you want to make the pad a little larger than the contact area, particularly in the direction away from the package.  I often at 20 mils past the end of the pin.  This allows for a little initial alignment error, leaves a place to put a scope probe, and makes it easier to visually inspect the solder joint.  On this inside, I usually just leave 5-10 mils.

In your case, there are two rows with the outer row covering up the inner row.  There is little reason to extend the pads for the inner row.  However, you want to treat the two rows symmetically so that the surface tension of molten solder on one row doesn't pull the other off its pads.  You also need to make sure there is sufficient room between the pads of the inner and outer row.