You've got two options to get set up:

Contact the developers directly through the support server. This is the simplest and fastest way to get set up for all! When you're ready, join the official bot support server and get in touch with one of the developers, who will guide you to add DisCog to your server.

Alternatively, you can create a server request on GitHub. This is a bit more complicated, but it's a good option if you're a developer. When you're ready, create a new issue in the official GitHub repository and follow instructions to create a server request.