This site here bbpress.org uses a customized theme and customized code to achieve the results in the pictures you show above.
I suggest you have a read of some of the tutorials in our docs, much of what you want has been documented in the codex.
Step by step guide to setting up a bbPress forum – Part 1 – Getting it working
Step by step guide to setting up a bbPress forum – Part 2 – Styling bbPress
Step by step guide to setting up a bbPress forum – Part 3 – Changing layout & functionality
Step by step guide to setting up a bbPress forum – Part 4 – Adding Actions
Step by step guide to setting up a bbPress forum – Part 5 – Using filters