1, select the template, if there is no template, then choose "other install media", here I choose "other install media", click "Next", 
2, to the virtual machine from a name, fill in the name, click "Next " 
3, select the ISO image, if a step choose an existing template, ignore this step, I chose to install centos7 image, click on" the Next ", 
4, select the storage host, click on" the Next ", 
5, distribution CPU and memory, click on "the Next", 
6, GPU not, click on "the Next", 
7, add a disk of the virtual machine, click on the "the ADD", 
8, allocated size of the disk, here I give 100G, click "Add" adding completed. 
9, I was here before has been added, to see the added hard drive, click on "the Next", 
10, select the card, click on "the Next", 
11, clicking "create now" to complete the creation VM, 
12, VM you just created, click console, install the system, I will not install the system.
hope this helps.