Just start would be my advice. Thats the hardest part. Starting, and then keeping at it afterwards. Writing is hard work. there is no secret sauce, there is nothing special to make it easier. You have to be prepared to knuckle down and just do, even if you have no motivation or inspiration.

Find a smaller forum or two you like, and start posting there, get feedback, then use your backlog to post on a larger platform like Royal Road as well. With luck and good writing you'll get readers and feedback. Because luck is a part of it.