Cannot find the "Open exercise system" link at below page of Business Architect Essentials

"Introduction to Pega Platform" -> "Pega Platform" -> "Exercise: Guided tour of Pega express"

Can you let me know what I'm missing? Thanks.

Update 18Jun: Now the link is visible and I'm able to access it; not sure what changed in the past day ?! If anyone had taken a step to resolve this, thank you!