Asalamu wa alikum,
What would be the subdomain for Islam site? islam.stackexchange.com or something else?
If you are committed to the proposal you will soon (probably within a couple days or weeks) get an email with an invitation to the new site's Private Beta phase, and it will include the URL you'll need to log in.
If you are not committed to the proposal, then once it reaches public beta, there will be a link to the proper URL on the area51 page for the site.