How to start using WPMUDEV? I just purchased the service.

Hi,

I would like to know what the next step after installing the plugin?
Can I use my existing theme? or do I need to use one of you themes?.

I just starting to go over your site. Hopefully, I'll find my way around to the answers.

Any help is appreciated, I'm a newbie to your services.

Sincerely,
Stewart Y.