Configuring Notifications
For Notifications, we need to provide the credentials for Telegram and Twilio(_optional_) and select the Email Account. This has to be only done once.
Telegram
In the Incident Management Settings Doctype, we need to provide the Telegram Bot Token and a Telegram Chat ID for sending notifications via Telegram. We can get the Telegram Bot Token when creating a new bot and Chat ID is the ID from telegram for a group or chat.

You can read more about it here. Currently for notifications we will be using a bot called "Frappe Incident Bot" and the Chat ID will be of the Sales and Support Group in Telegram.

On adding the credential a web-hook to Telegram with the ERPNext instance URL+endpoint which will be used to receive the updates from Telegram. You can cross check that by
$ curl 'https://api.telegram.org/bot{token}/getWebhookInfo'
If anyone has deleted the bot token and Chat ID accidently, contact the SRE team to get the credentials.
Twilio
In the Incident Management Settings Doctype, we can provide Twilio Credentials for receiving SMS for a new Incident. For sending SMS we need to provide a Twilio Account SID, Twilio Auth Token and a SMS enabled phone number from Twilio. You can get the Account SID and Auth Token from your Twilio account dashboard and you need to get a Twilio phone number with SMS enabled from the Phone Numbers section. You will receive a SMS notification from this number for any New Incident.

For receiving emails on Incidents, we need to provide an Email Account in the Incident Management Settings DocType. This is the linked to the Email Account DocType and the Email Accounts with Outgoing Enabled can only be used.

Configuring Incident Team
Keep in mind to save the Incident Team Doctype as "FC" and "SRE". FC should include the details from the Frappe Cloud team and SRE should include details of the SRE team.
The Phone Number field is optional because phone number is only used to send the SMS notifications for a new incident. If not everyone is handling infra related incidents, then provide the phone number of those who are.