To configure Firefox's proxy settings, open "Preferences". Make sure that you are inside Firefox "General" section. Navigate to the "Network Proxy" subsection and click on the "Settings".
Select "Manual Proxy Configuration". Type your proxy server hostname or IP address. If you are configuring a local proxy then this is "localhost" or "127.0.0.1". The port is your proxy port in your Feeds settings. For example, if you are using proxy feed "proxy://localhost:8080", the hostname is "localhost" while the port is "8080". Before you commit the change, ensure that "Use this server for all protocols" option is selected. This will ensure that AppBandit can capture both encrypted and non-encrypted HTTP traffic.
Intercepting encrypted traffic requires some additional setup steps which will be useful at a later stage. Specifically, you need to import AppBandit CA signing certificate. To do that launch AppBandit. Navigate to "Preferences" from the application menu. Click on on the "Certificate" section. Identify the "default-cert.pem" file and click on the "Save Copy" button to save the certificate at the location of your choice.
Open Firefox. Navigate to "Preferences" and then select the "Privacy & Settings" section. Here you will find the "View Certificates" button. Click on the button to open the "Certificates Manager". From the manager, click on the "Import" button. Select the exported certificate to import.