Once you get your login information you will want to verify your domain goes to your new hosting. If you have your own domain and bought the hosting you will want to point your websites "A Record" to your new web hosting's ip address. You should be able to find that in your new hosting panel. If you cannot find it you will need to submit a ticket.
Whenever you get your Domain's A Record pointed to our hosting will need to install your website. Many websites are hosted with Wordpress and you may want to use it for your website as well. If you are installing on a cPanel server you can use Softaculous to install wordpress. The install is very straightforward and simple. From there you can make your website with an interactive website builder.
If you are using ApisCP you will have an "App Installer" where you can choose Wordpress and install it that way. Be sure to use Let's Encrypt to setup SSL Certificates.