Do you already know the premise of the story you want to tell?
-Try just writing a few plot points that reflect the premise/story you want to tell, whether it focuses on the world, or the character(s).
-I'd also make character sheets describing appearance, personality and behaviors, likes/dislikes to start.
-Then write out your first paragraphs and see if you can make it all flow together and experiment with the relationships/dynamics/dialogues of your characters.
-Write a first draft and get critiques (if you want) and try to improve on it incrementally.
-As for drawing, it's gonna take practice, same as writing. You can scribble a few thumbnails to accompany your writing. You'll develop your own style the more you do it. I'd suggest Youtube/drawing tutorials to begin.
Sorry if it's a bit vague, but start small and build up. Make some time every day to write/practice drawing and you'll have a story after some time. And don't fret, no one is perfect the first time.
If you need, like a template for a novel/comic script, I'd suggest Celtx, if it's to your liking. There's also Good Drive, Google Docs, etc.
-Do some research on writing/genres/styles, it'll help too.