Trying to create a lan-to-lan vpn between two differents networks

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Hello

I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls in two different networks.
Can anyone tell me if it's possible and, if so, give me some advice on how to set up this VPN?
Thanks in advance ^^

P.S : i'm french, so my english can be a little bit clumsy.