Please help: RBLHGG-60adkit Basic Setup

Hello,
I bought the antenna kit, just mounted it and want to connect two LANs together, which are currently connected by another solution (TP-Link Bridge) via WLAN. Both LANs have the same subnet address (192.168.2.x). There is an internet router (FritzBox, 192.168.2.1) connected to one of this LANs. All PCs get their IP address via DHCP from the FritzBox, some devices (printer, NAS…) have static addresses. The two antenna routers have the default IP addresses 192.168.88.2 and 192.168.88.3, additionally I have assigned two static IPs to the two antennas in the specified subnet (192.168.2.2 and 192.168.2.3). What do I have to do to connect the two LANs to each other? I’ve tried everything possible, but I can’t get the bridge to work. The FritzBox sees both antennas and I can access them with the assigned IPs (WinBox and WebFig), but PCs on the LAN where the FritzBox must be accessible via the bridge don’t get any connection and no IP assigned via DHCP. Please help me as soon as possible, thank you very much.
Greetings from Germany, SugarShane.