Once you have a plan, start creating some tasks. The best thing to do is often to start with high level tasks, but if you do know specific things you must do, then get them down. What’s really important at this level is to get the things that need to be done rather then how to do them. Often a good starting point is to simply list the things you must produce prefixed by Create or Generate. Otherwise (or as well), you can brainstorm ideas if there is more than one of you or indeed search the web to see if there are example lists already available.
The key point here is not to worry about structure or whether you have got it all right – you can (and will) add, delete and change things later as you become clearer on what is needed.