It is my opinion that the first step in building a Data Vault is to start by modelling the target and the best approach that I have used is ELM. For me, the easiest way to get the core logical model defined is to use the easiest "low" tech approach quite often pen and paper or if you are fancy sticky notes and a whiteboard.
Quite often I'm in a meeting with customers and we will just be having a chat. In that time I will just listen for keywords and either write them down or just type them in notepad. The meeting rooms now all seem to have bigger and bigger screens so why not use it to create a logical model as you go. In this webinar, I'm using completely free software to show you how easy it is to create a logical model in minutes without complex software, it really is as simple as writing notes.