There are few ways to install Operating System (OS) to the Virtual Machine (VM), one of the popular way is Upload an OS ISO image to the Host Machine and then mount that ISO image as a CD/DVD ROM and install the OS with it. Here is how to mount the ISO image to the VM.
1. After you log in to the VM Host machine via VMware vSphere client, right click the VM you want to install the OS and choose Edit Settings.
2. In the hardware window, click the CD/DVD drive. In the Device Status, make sure Connect at power on is checked. Then select the Datastore ISO File follow by clicking the Browse… button.