[ubuntu] Create environment company computer through virtualisation on ubuntu server

Hello folks,

I only know install virtual box and create a virtual machine on Ubuntu desktop, with environment graphic desktop. I want learn how create virtual machine in ubuntu server (headless) through common desktop with environment Ubuntu. The goal is use the ubuntu server to management all my virtual machines and access them through my desktop or laptop. Another goal is create a networking, simulate environment company, with my ubuntu servert to create communication between machines with windows 7 and Linux.

How and what can I read to learn more about this matter? I remember which my knowledge about this topic it is very little and I am a newbie in Linux and even more on ubuntu server's.

Thanks