Marketing Campiagn and Sales order integration

Hello,

one can create and launch a marketing campaign. Its successs is measured with the number of sales orders generated (in my scenario). Here I have some very basic questions:

1. How do we create a link between a campaign and sales order. Where do we see refernces of each other in a sales order or campaign........i.e, in which tab pages in sales order or campaign respectivley

2. How does a campaign get reflected in a sales order. To do so what kind of customizing is required .......in campaign/ sales order

3. If the intended campign is not reflected in sales order, what needs to be done to facilitate correct campign determination.

Request for guidance.

Thanks,

Raju