Waqas, here's a quick and dirty guide to set up a new EXOS-VM in VirtualBox for OS X. The GUI for Windows is a bit different, but the steps are similar.
Create a new VM
Select Type: Linux and Version: Linux 2.6/3.x/4.x (32 bits)
You don't need much memory to run the VM. I use 256 MB. Adding more does not make much difference.
Don't bother much when creating the disk, as we will delete this later...
Once you have finished, select Settings and then Storage. You will see that the disk was created as SATA. Delete it.
Select the IDE Controller and select Add New Virtual Hard Disk.
Select to create a new disk.
I usually use VMDK format, Dynamic Assignment and no more than 400MB, but you can choose whatever you want.
After that, select the Optical Drive and put the ISO file in it.
Once you've done all this, your VM should look like this and you are ready to start it.
When booting from the ISO file, it will ask to erase the virtual HD and set up a partition scheme. Say Y.
When the process completes, it will ask for a reboot. DON'T REBOOT YET.
Before rebooting, remove the ISO file from the optical drive, or the previous process will repeat again.
Now, you can reboot. The VM should start normally.
You can find more information on configuring the management port in your VM in this post:
https://community.extremenetworks.com/extreme/topics/exos-vm
Hope this helps.