You want to scan a target before, during or after a deployment. This can be beneficial if subsequent steps may have conditions that previous steps perform. Or for those large baselines that have many different Nested Packages that may rely on a PDQ Inventory condition. This can also reduce the need for PDQ Inventory to scan all of your targets when you only need to scan the collection your targeting, for large environments this can improve performance.
Use the Scan Step. This allows you to select the scan profile you want and also control the timeout for the scan.
Lex provides an introduction to the Scan Step, just one of the many steps you can use in creating or editing a package.