Asma regardless how many account types you have. As long as you have more than 1 account type and assigned several questions to different account types, your registration form breaks down into 2 parts. If you want to break it down to 4 steps - this is a custom code modification.
You're free to do that on your own or hire a programmer. You can do that here: http://www.oxwall.org/market/specialists
Also you can make a post in the custom code modification section of the forum, probably some community member will assist you with that.