Hi,
I'm a developer, but a Minecraft beginner, so please be patient about my questions.

What I want

I want to build, deploy start this mod

What I use

I use MultiMC 5 and was able to add a instance

build

I use IntelliJ community edition and I'm able to build successful.

deploy

So my main question is, how (and what) to deploy and apply to instance of multiMC5 ?

If you can build successfully, the mod .jar file is saved in build/dist/. You can install this like any other minecraft forge mod, though I'm not too familiar with how this works in MultiMC