To use Charles for WebSockets package crawling, you need to complete the following steps:

1. First, make sure that Charles has been installed and configured correctly.

2. Configure the socket port on Charles.

3. Configure the global agent on the mobile phone, select socket5, configure the IP and port number, and start the global agent. Note that different mobile apps may have different global configurations, and some need to be opened where the nodes are configured.

4. After the configuration is completed, open VPN, and Charles will prompt you. Clicking Allow allows you to start crawling the data.

5. The captured data may include packages of http, https and websocket. You can view the data package in plain text by selecting the content, or you can view the data package similar to the chat interface through WebSocket option.

Please note that in order to grab the https package, you need to install the certificate of blue and white porcelain. If you want to track the connection of websocket, you need to make further settings.