In DG3 you can always use the Django admin module to manually register new users. To register users you then put /admin/auth/user/ to the end of your url and login with a staff user that also has super user rights. 

This is not convenient if you expect a lot of random users on the Internet to use your site. To make users able to self register, you then have to create a custom registration page that needs no authentication. The simplest form will work like this:

Simple registration in user only

Create a new page to be used for this purpose. A normal place to add it would be in the authentication folder that was added when you enabled authentication and call it "registernewuser". If you make sure to use all lower case and no spaces, this will also become the url for the registration page /authentication/registernewuser/ that then can be linked to the registration/login link on the base template. There is no extra settings to be done to the page properties except for setting Initial action to "new record only". The default box element should be switched to html type. The reason to set the page to new record only is to make it impossible to edit username by the registration page. 

Adding fields for internal data table

When creating a user registration page, you add data to an internal data table. To do this you simply add the fields and manually gives them useful names. Then click on the fields in the code and add "form-control" to style and manually set datamap to internal and the different fields to add. 

For users this usually are email, first name, last name and password. DG3 supports username as well, but if left out, the email becomes the users identification. Users tend to be more likely to remember their email address rather than a username. In the example we add both. To finish it up we add a big green button named register that do a standard update en redirect.

<h1>Register a user</h1>
<div class="row">
	<div class="form-group col-xs-12">
	<label for="">Username</label>
	[! field username !]
	</div>
</div>
<div class="row">
	<div class="form-group col-xs-12">
	<label for="">First name</label>
	[! field firstname !]
	</div>
</div>
<div class="row">
	<div class="form-group col-xs-12">
	<label for="">Last name</label>
	[! field lastname !]
	</div>
</div>
<div class="row">
	<div class="form-group col-xs-12">
	<label for="">EMail</label>
	[! field email !]
	</div>
</div>
<div class="row">
	<div class="form-group col-xs-12">
	<label for="">Password</label>
	[! field password !]
	</div>
</div>
<div class="row">
	<div class="form-group col-xs-12">
	[! button register !]
	</div>
</div><br>

The final code.

The simple registration page. We will add all the extras expected like two password fields, field validations and error checking in later documents, but this has all it takes to do registrations of new users.