There are several ways to access a dedicated server.
If your provider provides a web-based access panel, you can directly login to your website, sign in to your account and start accessing your server.
If you are using a localized dedicated server, you need to tweak a few of your IP settings.
Go to Start and click Run.
In the run box, type in mstsc.exe. This will open a remote desktop for you to access.
Type server IP and click connect.
The next screen takes you to the authentication. Enter Username and Password.
You can now access your dedicated server.