Best way to deal with connecting 2 sites via fibre

I currently have 2 sites which are independent and I use a VPN to connect the 2 and each has it's own subnet.

I am getting a fibre link by my provider which will be plugged straight into my switches and will essentially connect them up, I am not sure what the technical term for this is but they have assured me that is how it will work.

Given the following subnets, how do I get them to talk to each other? Will it just work because of the routing that is already in place at each end or do I need to do anything else?

Site A 192.168.1.0/24
Site B 192.168.2.0/24

Thanks