bbPress.org

1. How can I get people visiting on the website to login in or register and view their profile? Whenever I look at my website in incognito mode, there is no sign up or register button or view profile button.

You may need to add login or register menu items, or you can use the bbPress login widget and add links to your default WordPress register page or the page you put the [bbp-reigster] shortcode.

2. If people can register, how can can that registered person create a new topic? I can’t seem to find that tab thing on bbpress on my website.

What tab thing? just scroll at the bottom of a forum you created and you should see a topic form.

3. How can I make the forum so that only registered people can reply and non registered people to only look at the forum?

I think as long as you do not have any private forums or enable anonymous posting you can do this by default.

4.How can i get registered users to unsubscribe

You are not really specific on what to subscribe to, but you can unsubscribe to forums and topics by following this guide. You can only unsubscribe to forums and topics if you are already subscribed to them though.

Subscriptions

In other words how can i make the forum on my page like the one on bbpress ?

Hard work and custom development.