When you set up a Hub you can choose whether you would like the Card Layout or the Feed Layout. You can have a different layout per Hub if you like. If you would like one layout for the entire Space, you can set this up in your Space Settings.
Card Layout - Ideal for smaller, video-centric communities
This horizontal layout will transform all of your posts and replies into cards that can be viewed in a vertical thread. You can easily view posts by selecting them. Older posts are marked as older and these can be viewed by selecting Older.
Feed Layout - Ideal for larger group discussions
This vertical layout allows you to view your posts as a feed. To view replies, go to the speech bubbles (where it says 5 replies) and you will be able to view the replies underneath the main post.
How to Edit Your Hub Layout
To choose either the card or feed layout, go to your Hub settings and select which layout you would prefer for your Hub.