The IPv4 Address is now 192.168.1.69, same as my internal IP address. Do I manually change this (to what), & is this the same address I use in step 2 for the Private IP address?
I assume that you mean this address is the Private IP address currently assigned to the Filemaker host ... correct? I would guess that this address was assigned by the DHCP server in your AEBSn. Note, it is a dynamically assigned address. That would mean, it could change to any IP address within the DHCP address pool.
What you want is to assign a static Private IP address to the host ... so it doesn't change over time. The instructions I provided earlier shows you how to use DHCP to assign a "static" IP address by reserving a single dynamic IP address from its address pool. You can assign any address (even the current one) from the DHCP pool by using the DHCP Reservation feature within the AirPort Utility. Whatever address you decide on would be the one entered as the Private IP Address when mapping port 5003.
Since Filemaker says to forward port 5003, is this the number I use for all 4 UDP/TCP ports?
If Filemaker did not explicitly call out UDP or TCP, it won't cause any harm to use both ports ... so, yes, you would enter 5003 for each of the port entries in the mapping window.
What you are basically doing is telling the AirPort Extreme that any time it get a request from the Internet on port 5003 to direct that request to the host device listed with the Private IP Address (from the Port Mapping window).