How to Add new Disk on Azure Windows server and make visible.

I created a new VM1 using the new Azure portal (Resource manager?) and attached a new drive (4 GB) to the vm1. and when I RDP to VM1, I can't see the new drive. I deleted the drive and added one of 20gb as I think that there may be a 20gb limit on drives for A0. Still nothing.
Using this Microsoft link I fixed the issue: 

https://docs.microsoft.com/en-us/azure/virtual-machines/windows/attach-managed-disk-portal?toc=%2Fazure%2Fvirtual-machines%2Fwindows%2Fclassic%2Ftoc.json

How to add a data disk

1. Go to the Azure portal to add a data disk. Search for and select Virtual machines.
2. Select a virtual machine from the list.
3. On the Virtual machine page, select Disks.
4. On the Disks page, select Add data disk.
5. In the drop-down for the new disk, select Create disk.
6. In the Create managed disk page, type in a name for the disk and adjust the other settings as necessary. When you're done, select Create.
7. In the Disks page, select Save to save the new disk configuration for the VM.
8. After Azure creates the disk and attaches it to the virtual machine, the new disk is listed in the virtual machine's disk settings under Data disks.

How to Initialize a new data disk

1. Connect to the VM.
2. Select the Windows Start menu inside the running VM and enter diskmgmt.msc in the search box. The Disk Management console opens.
3. Disk Management recognizes that you have a new, uninitialized disk and the Initialize Disk window appears.
4. Verify the new disk is selected and then select OK to initialize it.
5. The new disk appears as unallocated. Right-click anywhere on the disk and select New simple volume. The New Simple Volume Wizard window opens.
6. Proceed through the wizard, keeping all of the defaults, and when you're done select Finish.
7. Close Disk Management.
8. A pop-up window appears notifying you that you need to format the new disk before you can use it. Select Format disk.
9. In the Format new disk window, check the settings, and then select Start.
10. A warning appears notifying you that formatting the disks erases all of the data. Select OK.
11. When the formatting is complete, select OK.

Next steps

• You can also attach a data disk by using PowerShell.