We are glad you have it figured out relatively quickly.
TRiLOGI + TLServer is designed to be client-server pair and they interact by TCP/IP. Unfortunately it means it is less straightforward than a software that only connect to the PLC via serial port (such as WinTRiLOGI does with E10 and H-series PLC since it doesn't support TCP/IP networking).
The advantage of implementing the client server model is that a PLC model without Ethernet (e.g. T100MD+) can be connected to a PC running the TLServer and allows the PC to act as the TCP/IP gateway for the PLC. This allows T100MD+ PLC to be accessible from the LAN or the Internet even though it does not have Ethernet port built-in.
Since Nano-10 PLC and F-series PLC,have built-in Ethernet port and can connect directly to LAN, they can be programmed or configured directly from TRiLOGI using TCP/IP network connection without using the TLServer. However, you must know the PLC's IP address and it must be in the same subnet as the PC in order to be accessible by the TRiLOGI software.
So the alternative method of connecting to the Nano-10 PLC is via its RS485 interface and thru the TLServer software. In this case since the TLServer can be running on the same PC as the TRILOGI, its IP address is not important and TRiLOGI can connect to TLServer using the localhost IP address (127.0.0.1). TLServer relays any hostlink commands it received from the TRiLOGI software and send to the PLC via the serial interface and vice versa,;
So you can see that regardless of how the PLC is connected to the LAN (direct Ethernet or via TLServer), you use TRiLOGI exactly the same way. The difference is only the IP address. This gives a seamless interface for user of T100MD+ to migrate to the Nano-10 or the F-series PLCs.