Adding a BNB network (bsc network)

Hello, I want to add BSC network by default in networks.
I want it to be BSC by default, not ETH network.
I couldn't find which files I should add this to.

I added it to util/networks/index.js but the working functionality is broken.

Start by reading util/networks/index.js and tracing the existing network configuration and default-selection path, since the issue reports that a direct edit breaks functionality. Verify that BSC is available by default and that the intended default network still works without breaking existing functionality.

Written by the indexing model from the issue text.