After you have created the Infinite Campus assignment and aligned it to a Naiku assessment, you can view that assessment in Naiku.
In the details of your assignment, click on the Name of the Naiku assessment. Below, the name of the Naiku assessment is "Quick Key Quiz 1".
When you click on this, you'll be taken to the "Watch Progress" screen for that assessment in Naiku. This allows you to see which students have started the assessment and how they are doing. From this same screen, you can Close and Score the assessment in Naiku after all students have completed the test.