B0 distortion correction

I am trying to do a distortion correction using (epidewarp.fsl)
–mag mag.nii.gz
–dph dphase.nii.gz
–tediff YOUR_TE_DIFF --esp YOUR_ESP
–vsm bold/b0dcmap.nii.gz

The issue we collected two field maps one in the AP direction and one in the PA direction (hence I have two mag and phase volumes). I. am not quite sure how if I should create two different maps and keep them in my bold folder for my FSFAST pipeline