cd ./Downloads
download installer: https://portswigger.net/burp/releases/professional-community-2023-12-1-1?requestededition=community&requestedplatform=

chmod +x ./burp*.sh
./burp*.sh
run through gui installer

when complete, open terminal and launch via: BurpSuiteCommunity
  - or find it in the menu
  - or in the installation directory (default: /opt/BurpSuiteCommunity)
  
Note: Free Community Edition does not allow you to load or save projects

Most important thing to cover is configuring Burp to be your browser's proxy. This example will show how to do this on a Linux system Running Firefox.

Click the Proxy Tab, then click Proxy settings (sub tab)
In the new Settings window, click "Import / export CA certificate"
Select Export > Certificate and private key in PKCS#12 keystore
Save file as burpcert.ca to ~/Documents
Enter password (required). This will be used during the import process. 

Load up Firefox
Click the App menu button > Settings
Click Privacy & Security (left menu)
Scroll down to Security > Certificates, then click "View Certificates..."
Click the "Your Certificates" tab, then click Import
Enter password from the export process. 
Click Ok/save/whatever to close all the windows. 

Back to the Proxy > Settings window in Burp, verify the Proxy listener is setup and running. By Default, it will be listening on port 8080
Back to Firefox, in Settings, click General (left menu)
Scroll to the bottom and you will find Network Settings. Click the Settings button
Select Manual proxy configuration. 
For HTTP Proxy, enter: 127.0.0.1
For Port, enter: 8080     #note: update as necessary
Check the box "Also use this proxy for HTTPS"
Click OK to save. 

Go back to Burp. Close the Settings Window
Click the "Intercent is off" button to turn it on. 

Restart Firefox and test. 
A warning will likely pop-up about untrusted cert. This is because Portswigger is now acting as a middle-man. You may approve after review

When done testing, you'll end up closing burp. Your Proxy will fail now, and firefox will seem broken. Go back into Networking settings and disable the proxy. 

...or you can just use the buit-in browser and save all of that hassle.