I am doing the same MStef. I am writing query as below :
SELECT [Trainee-info].[Emp-Id], [Trainee-info].Fname, [Trainee-info].LName, [Trainee-info].Institute
FROM [Trainee-info]
WHERE ((([Trainee-info].[Batch-Id])=Forms![QBF-Form]!batch) And (([Trainee-info].[Th-No])=Forms![QBF-Form]!thno)) Or...