How to backup ESXi 5.1 VMs

Hello,

I'm using esxi 5.1 free edition, have installed 4 VMs on it (servers 2008 R2) and using VMware vSphere Client to manage them.

I'm new to esxi environment and don't know how backups works on it. Can you please guide me what is the easy way to backup vms and restore them?

Thanks.