Step1: Every Webinar you create has some tools with it. The second tool with a pencil icon reads 'Edit/view Webinar Details'
Step2: Click on the 'Simulated CTA' icon indicated in the below image.
Step3: Click on 'ADD SIMULATION CTA'
Step4: Enter CTA Message, Link, Button Text, Time out, Trigger Time.
Step5: Click 'Save CTA'