NOTE: Make sure that you already set up Wilmer-Api in order to be able to connect to it. Choose an Open WebUI friendly example user.
This is harder than it sounds if you don't already have docker. There are tutorials all over for it, but be prepared that this might be a little challenging.
Once you have it set up, you're good to go though.
Once you're in Open WebUI as either an admin user, or no authentication instance, you should be able to click on a little person icon at the top right and go to settings.
Once in settings, there should be an "Admin Settings" on the left.
Once in Admin Settings, there should be a "Connections" options.
WilmerAI can be connected to as either an OpenAI or Ollama connection, but I recommend Ollama. I find the quality far higher. Put in the API connection info found on the console output of Wilmer if it is running
You should just need to type in the IP/port like the image above, and click save at the bottom right
Once you've saved your settings and exit the settings area, you should be able to see Wilmer as a model in the model dropdown at the top center. If you don't, sometimes I have to reload the page to make it show up.