As @mohammed said in his comment, you should have a look at static routing.

Let's suppose the router A (192.168.0.0) wants to communicate with the network behind the router B (192.168.2.0).

Using static routing, you'll simply add an entry in the routing table on the router A to tell "if I have a packet for network 192.168.2.0, I'll send it to the router 192.168.2.1 using my interface xxx".

Don't forget to also create a static route on the router B (if you don't, the communication will be unidirectional).

As @mohammed said in his comment, you should have a look at static routing.

Let's suppose the router A (192.168.0.0) wants to communicate with the network behind the router B (192.168.2.0).

Using static routing, you'll simply add an entry in the routing table on the router A to tell "if I have a packet for network 192.168.2.0, I'll send it to the router 192.168.2.1 using my interface xxx".

Don't forget to also create a static route on the router B (if you don't, the communication will be unidirectional).

EDIT: according to @JacobEvans comment, I'll add that you'll also need a network between your 2 routers. You can use a site-to-site VPN (maybe your Vilfo router can do it) or a peering network, but I'll recommend a VPN since it's simpler to create.