To create commitments from a contract of affreightment use the VMS java client and navigate to the module COA Planner.
Select the model voyage you would like to create commitments from and use the Auto Schedule button to create a set of voyages from this model voyage.
Next use the Create Unallocated Voyages button to make these voyages show up in the master schedule of FAS.
The voyages are now shown as a commitment in FAS and can also be found in the Booking and Operations Module under Unallocated.