In the Telegram Messenger App you can select the bot (like you want to start a chat) and click on the name of the bot on the top. A menu will appear where you can select the messenger behaviour when a messages arrives. This can be done for all users/bots separately.
I do not use a way to force sound alerts on a silent phone. I imagine this could be done using the Tasker app of some similar kind of phone automation app.
Please check the wiki of the github page of node-red-contrib-chatbot. There is a lot of explaining and examples.
EDIT: I added the wiki link to the first posting.
I don’t use it for HA yet, because I just started exploring HA, so I’m a complete noob in there… 
My goal is to setup it using MQTT. But at the moment I don’t have a working example where HA is involved. For all my other sevices/IoT/Node-Red it is working like a charm.
EDIT: FYI, see my first steps to accomplish this on this topic:
https://community.home-assistant.io/t/my-first-steps-discovering-home-assistant-setting-up-a-ha-client-to-an-existing-mqtt-broker