virtualbox.org

good afternoon,
I installed virtualbox and now I should create a virtual machine CernVm and make simulations in it.
I tried to do it but it does not work. can someone help me?
thsnks

You sound like a fairly new user to VirtualBox. Since you are expected to know some basic terms before we engage in a meaningful discussion, I would suggest to start by reading three small chapters from the User Manual:

• 1.2. Some terminology,
• 1.7. Creating your first virtual machine and
• 1.8. Running your virtual machine.