Below is the config steps for a wireguard site to site config. Sensitive information has been left out.
Wireguard interface and Peer.
/interface wireguard add comment="Site-to-site to Gentian" listen-port=14034 mtu=1420 name=wg-gentian /interface wireguard peers add allowed-address=10.34.14.2/32,192.168.14.0/24 comment="Gentian site" endpoint-address=home.14gentian.au endpoint-port=14034 interface=wg-gentian \ name=peer-gentian persistent-keepalive=25s public-key="fCuSHk4h2Y0qVzmDlwhr99A2KJyAONNrKSNGw8+rnxI="
Wireguard interface IP address.
/ip address add address=10.34.14.1/30 interface=wg-gentian network=10.34.14.0
Route for Wireguard interface.
/ip route add comment="to Gentian LAN" dst-address=192.168.14.0/24 gateway=wg-gentian
Firewall rules.
/ip firewall filter add action=accept chain=input comment="Allow WireGuard" dst-port=14034 protocol=udp add action=accept chain=input comment="Allow all from Gentian via WG" in-interface=wg-gentian add action=accept chain=forward comment="WG to Gentian" out-interface=wg-gentian add action=accept chain=forward comment="WG from Gentian" in-interface=wg-gentian