ACNHSpawner is pretty straight forward. Open the folder acnh-software and then ACNHMS_Win. Double click ACNHSpawner.exe to start the program.

On your switch, press Home – Settings. Navigate to Internet. Take note of the ip address. It will be something like:
192.16.x.x
10.x.x.x

On acnhspawner, towards the bottom, put your ip address in the ip address box and click connect. If you see ‘Connected Successfully, you are good to go.