Creating a 3D DCP in Xport only requires that you enable the 3D (stereoscopic) option in the Xport options. The rest of the procedure is exactly the same as those for creating a 2D DCP.
However, what is important is whether your source is in the right format required to create a 3D DCP. To create 3D DCPs, the 3D source files must be frame sequential (L and R frames interleaved) 3D format - QuickTime or image sequence. Currently this is the only format of 3D accepted in Compressor.
So, source files must be either QuickTime mov files at 48fps (24fps per eye, frame-sequential/interleaved) or an Image sequence with both left and right eye images in the same folder (each alternating file in the sequence should be L and R).
In both cases (interleaved QT or interleaved sequence of images) the first frame is always the Left-eye frame. In Xport you will select “3D” but the frame-rate must be set to 24fps (the default).
Currently Compressor can accept 3D sources only if they are interleaved LR, it cannot accept the L and R streams as separate files or sequence of images.