Write down you mnemonic to a safe place and treat it like a password. If you loose it, you will not be able to run the node.
If you lose your mnemonic after you have completed the bioauth enrollment, it will be impossible for you to authenticate in the network. We do not have a recovery mechnism at this moment, so you won't be able to participate in the TestNet anymore.
There is a chance that ngrok will "just work" without the key - but if it doesn't, you will have to create an account and provide your authorization key.
This section contains destructive actions, and have to used careully.