Can I install VSAN on a single physical server (lab environment) if that's all I have?
If so, do I install ESXi and vCenter first, and then install VSAN? What is the right order?
if you are planning to create Nested environment for lab practice for VSAN. see following blog posts, you will get step by step instructions to do so.
VSAN is a feature of vSphere 5.5 onwards which can be enabled if you meet minimum requirements to setup VSAN Cluster.