How can I install Lion onto VirtualBox, which is running on Yosemite?

Hi,

I've recently gotten a new mac, with Yosemite pre-installed. I really like Yosemite and don't wish to change, but I'd like to still be able to run my Logic express software, which only runs on Lion or older. If there's an easier way to do this I'd love to hear about it, but the easiest solution I could think of, was to run an older version of Mac on virtualbox. Is this possible and if so, is there a decent link to some instructions?

Thanks in advance,

Ryan