I installed LocalsTV via the Roku Website, but the channel is not showing up on my Roku Stick device. I don't know the model number of the Roku stick. It does not say on the device. It was purchased in 2014.
It’s quite possible that their app won’t load onto a device that is 10+ years old. (Each application writer gets to decide how far back they want to support.) You could try getting your model number and asking them.
https://www.locals.com/contact
If it's the 3420 that shows up in your post, that model hasn't received updates for a few years now. You can find the stick's model number displayed under Settings->System->About.