Hey @Jiayan Yu Racheal from the support engineer team here 

It is not possible to create a multi page Outbound Post but it sounds like Product Tours could help you out here! Product Tours allows you to create personalized tours, that guide customers to take the right actions in your product. They can be used to onboard new users, introduce new features and more. Check out this tour of Product Tours for more info - this was built using the actual product itself!  

You can also read this article on Product Tours to find out more.