Hello
the easiest way will be the "Auto Associate" function in the Workspace.
For Number and Desription. If no auto numbering in Object Init rules, you should be able to map them between CAD and WTPart (explicit map in the type manager if attributes have different name in CAD type and Part type).
If you want to keep autonumbering for WTPart. you will prpobably need to implement your own "Custom Class for AutoAssociate" (set in the pref manager)
. to be able to find or create a WTpart with the same number as your CADDoc
for drawing, you can set the "create content link" pref if you want a real persisted link in the database between your WTPart and the CAD drawing.
If you do not set this pref. You will have a automatic "calculated" link. not persisted , and based on the "as stored" configuration (ie when you checkin the drawing with the 3D model ...). but depending of the revising scenario, can lead to some historix issue.
by default , on CAD checkin. It will create the BOM. If the CAD are already checked in, you can use the "compare CAD to part" function in the action menu of CAD asm to synchronise your WTpart eBOM with CAD structure
regards
Gregory