Hello Binod
Yes, you are correct VPLS is indeed a Layer 2 technology, so there is no routing involved. VPLS is a type of Metro Ethernet, which essentially delivers a Layer 2 pipe to each of your remote sites.
VPLS is one of several implementations of Metro Ethernet that you can find out about in this lesson:
VPLS is sometimes called Ethernet LAN service.
How do you implement routing in this scenario? You do so on your own devices, completely independent of the ISP. Imagine that the Layer 2 connections that terminate at your remote locations conceptually act as a single Layer 2 switch allowing your sites to communicate using Ethernet. If you have a router at each site, then those routers can communicate with each other over Layer 3 by placing them all in the same subnet, and configuring your routing accordingly.
I hope this has been helpful!
Laz