Probably not to start by asking for advice. You'll get a wide variety of answers, any of which will contradict each other, and will leave you more confused.
I would say simply: Write. Write about what you want to write about, and don't feel daunted by the prospect. Write down the first thing that comes to mind, that might be the start of a story, the end or even just some character description. Use that as your starting point and keep asking yourself questions to follow up on what you've written.