How to do networking between virtual machines?

I want to create a network system in virtual machines.

I have 3 virtual machines. Such as, vm1-vm2-vm3.

vm1 have non-free internet. vm2 is a firewall. vm3 have free internet.

vm1 is taking internet over the vm2. (firewall has rules.)

vm2 is taking internet over the vm3.

How can I create the Lab System in Ubuntu?