With the BCH signer done, here is a guide on how to use it and keeping your stash secure.

-------- The signer --------

In order to sign for BCH, you have to pick your signer manually. This is a new feature, and is only available in Expert mode, so first thing first, set user mode to Expert.
To pick the signer, you need to get to the "Confirm Transaction" dialog. Once there, you should see the signer select frame, click it and pick the signer for the chain you want to spend on. The default option only picks between Bitcoin signers, to sign for BCH you HAVE to pick the BCH signer manually.

Screenshots for the good measure: https://imgur.com/a/9zXGD

Once you've picked the signer, the rest is business as usual. Note that this step only occurs at the point of signing, i.e. if you sign offline, you have to pick the signer on your offline machine.