DLC, release, and patch problems

Hello everyone,

so far, I have a big problem.

I develop a program and I package it for distribution.

I create new materials and maps and I want to add them to the packaged game.

I do not want to package the whole game and distribute it again. I only want to package the additional contents.

I think it is a DLC issue, and maybe relative to release and patch, after I go through official document. But I cannot get what I want.

Anyone can help for providing a solution or a thought? Thank you so much.