Download an iso image file of Ubuntu 14.04. No need to burn an iso image file to a DVD or CD-R.
Download VMware Player and install it.
To install Ubuntu, create new virtual machine and install OS later. Choose setting of virtual machine and click CD/DVD. Then, select 'Use iso image' and set the location of the iso image.
Do not choose Installer disk image file (iso) if you want to install non-English version.
vmware tools should be installed manually.
I installed some software and changed some settings as follows:
$ sudo apt-get update
$ sudo apt-get upgrade
Some useful packages may be installed:
$ sudo apt-get install gfortran
$ sudo apt-get install gv