How to organize a VPN multiple network (several offices in one network)?

Question

VPN

There is one VPS server on Win 2008, VPN is raised on it, offices 1, 2, 3 are connected to it. 1 office is located in the city of Karaganda, the rest in Astana.
Office 1: 192.168.0.0 / 255
Office 2: 192.168.1.0 / 255
Office 3: 192.168.2.0 / 255
In offices 1,2,3 there are computers (servers) with one network card on them, a new VPN connection was created without using the main gateway virtual network (so as not to drive traffic through the VPN), when connected to the VPN, they are assigned the address 10.0.0.2/5.
How to organize one single local network between offices? So that office 1 employees can access office 2, 3 and vice versa.
PS if the solution is in routes, then you need to assign routes on all computers in the office or only on those computers that are connected to the VPN?