Hi Pragti,
This is correct, what is your dobut in below line.
custIns.CommonMyCustomField = context.GetCurentSystemDate();.
you have to create an instance of Custom BO which needs to be schedule (this instance always be picked up by query used in MDR)
MDR fetched one instance of Custom BO and execute it's action, this action query required Customer BO instance and will update as per the logic.
If you are facing any issue let us know.
Regards
Sunil