How to set up printer wirelessly to computer on ethernet

Brother DCP-L2540DW

We recently had to change the set up of our router and wi-fi. I previously had my Brother printer linked with my computer wirelessly, even though the computer was not on the wi-fi. Since the change, I can only get the printer to communicate with the computer if the computer is also on wi-fi. However, I need the computer to be on the network so that other computers in the office can also communicate with it. I spent hours chatting with a Brother rep, but they were unable to get it to work. Hopefully someone has some suggestions...