Note: Your domain name should be pointed to your web hosting already.
Follow these steps below to login to WordPress's dashboard:
1. Visit the Wordpress Dashboard URL at: http://YOURDOMAIN.com/wp-admin
(where YOURDOMAIN is whatever domain you've set up on Magic Hosting).
If you install Wordpress to a sub-directory, then it would be: http://YOURDOMAIN.com/blog/wp-admin
(where /blog is whatever sub-directory path you've installed WordPress to)
2. Login to WordPress with your username and password.

That's it, now you know how to login to the WordPress Dashboard where you can install themes, plugins, and write blog posts among other things.
If you have any questions or run into any issues, please don't hesitate to open a support ticket and we'll be glad to assist you as soon as possible.