As an instructor in a scenario, you have the option to open the learner assessment forms during the scenario.
To begin you'll have to navigate to "Run Session"
To Assess Learners select the gear icon, then "Assess Learner"
You will then be taken to the Learner's Assessment screen, which will show all of your learners and their current assessments.
Click the "bubble" in the Assess category to pull up the assessment options for a learner.