How do I run a docker instance from a DockerFile?

I finally figured out how to get docker up and running.

docker run --name my-forum-nodebb --link my-forum-redis:redis -p 80:80 -p 443:443 -p 4567:4567 -P -t -i nodebb/docker:ubuntu

I linked it to a redis instance, cool.

This is from scratch and I assume that when I created the redis instance

docker run --name my-forum-redis -d -p 6379:6379 nodebb/docker:ubuntu-redis

it pulls the image from a remote repo?

NodeBB offers a Dockerfile https://github.com/NodeBB/NodeBB/blob/master/Dockerfile I am not really quite sure how to use it. I am assuming that I can somehow create a local environment by calling this Dockerfile on my remote.

Is this correct? If so how can I create the local instance pointing to the remote?

Download the file and from the same directory run docker build -t nodebb .

This will give you an image on your local machine that's named nodebb that you can launch an container from with docker run -d nodebb (you can change nodebb to your own name).

You cannot start a container from a Dockerfile.

The process goes like this:

Dockerfile =[docker build]=> Docker image =[docker run]=> Docker container

To start (or run) a container you need an image. To create an image you need to build the Dockerfile[1].

[1]: you can also docker import an image from a tarball or again docker load.