Go into your file explorer, select the "View" tab at the top and make sure the option "Hidden Items" is activated. Then navigate to
C:\Users\"Your Username Here"\AppData\LocalLow\Three Eyes Software\Silverpine
with the username of your computer account in place of the "Your Username Here" part. Open the file "settings.json", you can set the option "useAIServer" to "false" and "showAIModelSelectionOnStartup" to "true", this will have the game show you the options for running a model locally.
If you want to try connecting to the server again, you can change the "AI Processing" setting in the ingame settings menu to "Server". You will have to restart the game for it to actually try and connect again, though.