Can not access web interface after initial install

[KB8WFH]

Needing help with initial setup. Really confused.  I have installed PFSense before with no problems so I'm not a total newbe but this one is a mystery, especially since I can't seem to find others with this issue.

I have installed OPNSense on a computer with the standard installation. It has an  ethernet cable from the modem to one ethernet port on the computer running OPNSense, then have an ethernet cable going from the OPSSense system to a switch where I have another workstation plugged into the switch.

I have tried this two times on two different computers with the same results. Both times, it appears to install properly. It then reveals that I can access the local interface at 192.168.1.1.

However, when I try to access it through my workstation browser, it says the address is inaccessible. I check my local workstation's assigned IP address and it's something 169.254.238.120.  Why is my workstation being assigned such a goofball IP address and how do I get it on the same subnet and access the interface at 192.168.1.1? I even tried manually assigning my workstation to an IP of 192.168.1.3 or similar to forcibly put it on the same subnet. What am I doing wrong?

[cookiemonster]

https://docs.opnsense.org/manual/install.html
After setting up your interfaces, maybe you didn't setup dhcp on them. You need that service running on the interface that is your LAN so your devices get an IP address in the appropriate range, chosen by you. Don't forget to not use static reservations from the same pool as your dynamic.
And you need to disable the existing dhcp server on your network.

[fastboot]

https://en.wikipedia.org/wiki/169.254


I propose to read through some HowTo's...

1. Workstation OS and IP addressing
2. Installation of OPNsense
3. Switch configurations. e.g VLANs