Basic start here: https://developer.hashicorp.com/terraform/tutorials/azure-get-started/azure-build

Cheatsheet

az login Set your subscription az account set --subscription "35akss-subscription-id"

Next, create a Service Principal.

A Service Principal is an application within Azure Active Directory with the authentication 
tokens Terraform needs to perform actions on your behalf. 
Update the <SUBSCRIPTION_ID> with the subscription ID you specified in the previous step.

az ad sp create-for-rbac --role="Contributor" --scopes="/subscriptions/<SUBSCRIPTION_ID>"

SSH Keys

Azure uses rsa keys and not ecdsa it seems? ssh-keygen -t rsa