Create a new Custom Channel

Hello! Im trying to create a new custom channel with will be using an API to send the target group and content to a specific place. I haven't created a channel template from scratch, so Im a little stuck on what steps to take. 

What I have done:
Create a new External Account for the use of routing.

A new connector for the external accunt.

A new schema for the channel. Called communicationService.xml. (no content yet)

A new input form (no content yet).

A new javascript template. (no content yet)

A new test delivery based on the new javascript template. It only looks like this now as everything above is empty:

A new publishing Template to connect everything.

But Im kinda stuck on where to begin with these above.

As a start we want to have a titel and some text...

Hope someone can help with a good guide or where to start adding code.

Best Regards,

Martin