Since I’m redoing my kali linux box, heres another quick tip:
to properly setup Burp, you have to configure your proxy on your web browser.
open up Firefox and go to the menu on the right-hand side. click on the preferences, find the advanced on the left hand side of the screen and click it. Next, click on Network and finally, the first option is called connections, click on the settings key. On the connection settings, under HTTP Proxy type in 127.0.0.1 and for port, type 8080. These are the default settings of Burp Suite.
Once this is configured, open up Burp Suite. Follow the prompts until it finished loading. Go to the proxy tab and find the button that says ‘intercept is on/off’ and make sure it is on. navigate to a website, and you will see that it doesn’t load up right away. Go back to burp and see that the proxy tab shows there is a request waiting for you to modify it or just forward it. This is how you can pass info to the server, but that’s for another tutorial, hit forward and the web page should load.