Attach a disk to VM

Hi, 

I have a disk with my files, nopCommerce files in this case.

How do i attach this disk to a Vm, so that i can reach and edit the files from the RDP/MTSC?

disk info: 

portalvhdsty13h9c4s0w6d

Storage Account

Online

Hbxnc-sql

North Europe

according to this tutorial, there should be a "attach disc" and a "attach empty disc". i only have "attach empty disc available".

Thanx/Hobbe