Content Card in Latest
Publish the card(s) to My Feed in Studio (appears under Latest in the end user experience). As long as only a limited amount of content is published to My Feed and your program does not leverage Auto-Follow too much, publishing to My Feed will make the content among the first things that a new users sees after registration.
Include images to and text to encourage users to open the content card(s).
Content Card with Require Campaign
Create an article post and enable a Smart Campaign to target users that are already in your program. Set the Smart Campaign to Goal: Acknowledgement and Priority: High. This solution is not recommended for programs that are just launching, as users that join the program after the campaign has started running will not be pulled into the campaign. An Acknowledgement Smart Campaign would work best for an established program that has recently updated the Terms of Service - a way to say "check this out". A High Priority Smart Campaign will automatically follow-up with users that have not yet acknowledged the post.
Track Within Studio
There will be question-based groups that track which users have answered Yes and which users have not answered the question - you can target your email campaigns and push notification campaign to users that have not answered the question.
Track Outside Studio