To use the report filter parameter, create a WHERE condition (without the use of the word WHERE) but use a report field name. The method loads the report with records that are filtered according to the constraints you put on the report field(s):
DoCmd.OpenReport gsDocName, acPreview, , reportFieldName = Me.cboSubmtList
You must use proper delimiters if the value being passed by the combo is a date or is text (not if a number). Also need to ensure that you use the correct combo column if there is more than one.
If you'd rather modify the report recordsource, you can do that too - after you open it. Or you can modify the sql of the query that the report is based on. Many ways to skin this cat, but I'm getting to methods that are much more complicated and not really necessary!
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.