Advice for aspiring writers. If you have an idea but you're not sure how to transfer that idea from your head onto the paper or screen here's what you do... start.
Just start it doesn't have to be at the beginning, if you have a clear scene in your head just write it.
The problem many times is a lot of beginner writers feel they must have the scenes mapped out one after the other and they have to be perfect that's just not true. First off understand that there are going to be rewrites that's just part of the process.
The first draft is mainly to get the idea out of your head and down onto the paper, you shouldn't really worry about grammar at this point you mainly just want to get the idea out.
Once you start you see that the creative process will begin to flow and your story will begin to take shape and before you know it you will be through your first draft.