How do I make containers from "unused" images

Hi!
I’m a bit new to Docker and I tried to download ttps://github.com/SensorsIot/IOTstack
I already had Docker installed an it’s running HASSio.

It seems that the images were created but when I try to open them in Portainer, is says that they’re not registered as containers and are marked as “unused.”

Does anyone know how I can start them up?

When I typed: cd IOTstack
docker-compose up -d

I got :

Pulling webthings_gateway (mozillaiot/gateway:arm)…
ERROR: manifest for mozillaiot/gateway:arm not found: manifest unknown: manifest unknown

I thought that maybe I could remove “webthings” but I don’t see it in Portainer. I also see a few other images that are marked “unused” in Portainer that I’d like to be able to use. (e.g. a z-wave plugin for Home Assistant).

If anyone can help point me in the right direction, I’d greatly appreciate it! Thanks!