In the Basics blade you need to provide the basic details for your cluster:

You need to provide the following details:

1. Enter the name of your cluster.
2. Enter a User name and Password for remote desktop for the VMs.
3. Make sure to select the Subscription that you want your cluster to be deployed to, especially if you have multiple subscriptions.
4. Create a new Resource group. It is best to give it the same name as the cluster, since it helps in finding them later, especially when you are trying to make changes to your deployment or delete your cluster.
5. Select the region in which you want to create the cluster. You must use the same region that your key vault is in.