IP address conflict between computer and Roku Ultra.

I had fiber internet installed yesterday. An ethernet cable runs from the fiber modem in the basement to my computer area. There, I installed a Linksys SE3005 5 port gigabit ethernet switch so that my computer and my Roku Ultra streaming player could share the bandwidth.
Plugged the cable from the fiber modem and the cable from my computer into the switch. That works fine.
The problem comes when I also plug in the cable from the Roku player. The computer 'local area connection' disconnects and only the Roku is connected to the internet. I then get a popup saying "another computer on this network (which would be the Roku) has the same IP address as this computer."
I have to unplug the Roku and then disable/re-enable the local area connection to get the computer to connect again.
Is there a way to change the IP of the computer so that both the computer and the Roku can remain connected and share the internet connection?

I know nothing about this. Never had to deal with it before. My old router handled everything before I switched to fiber. I just plugged everything in and it worked.
I don't even know how to find the IP that this computer is on to compare it to the Roku. I only know that the Roku is pretty short on settings, so I thought the best approach would be to change the computer's IP to clear the conflict.
Unless somebody is familiar with the Roku Ultra, and a different IP address could be manually assigned there.

From what I can gather, it is not possible to manually assign an IP address to the Roku. It is normally assigned by a router.
My mistake was that I bought an ethernet switch instead of a router.
I have ordered a router and I believe that should take care of the problem.
Thank you for your replies.

Any networking hardware issue, from server, router, to computer peer to peer, an easy solution is to power down all, then power up one-by-one, per IP priority.

For your case, you can power down all, then power up router, then Roku, then phone/Tab , , , last would be the computer.
When all are up, you can check the router IP table. Roku should get its IP address right. If NOT, likely be taken by phone/Tab, then power off phone/Tab , , ,

And so on,

Setup priority, then one-by-one,

You will see they running fine.



Usually wireless device (Roku, laptop, phone/Tab , , ,) wouldn’t take static IP address. Desktop can take static IP address. printer may or may not.

Just so everybody knows, and to close this thread out, my issues have been solved by taking the ethernet switch out and installing a wifi router.
The computer and the Roku both coexist , and both have full access to the bandwidth.
This router is going back, because I cannot turn off the wifi which I am not currently using, but I have another one on the way that has the capability to disable the wifi. I can turn it back on if I ever require it.
Thank you again for your input.