There exist different cases.

1) If you have registered a subdomain.unlugar.com: You can automatically upload your page once that you are registered in UnLugar.com

2) If you have transferred an own domain: Even if the physic creation is done automatically, there exists a delay of between 48 and 72 hours for your entity to actualize the DNS data in your account.
We do not take charges of the delay because the updating process is not done by us, in spite, it is done by the Registration Entity for your domain (for example: nic.ar)

We will recommend you that, once that your account is registered, you upload by FTP at least one warning page that your site is under construction. In this way you will also be able to check that everything works correctly.