Hi Catie, seeing as Mac unlocked the thread, I’ll assume your username passes and respond.
The short answer to your question is yes - you can definitely fade lights in and out with a DMX controller. This will be by utilizing the “Dimmer” or “Intensity” channel on your fixtures, if equipped. Do you have the right DMX controller? Maybe. Assuming that you bought a DMX Operator, it’s far from my first choice, but it can work. You’ll need to read the manual for both your lights and your controller to make things work though. Sharing exactly what you bought for both fixtures and controllers will help.
To be bluntly honest though, based on how you asked your question and that you’re trying to start from scratch, you will likely save a tremendous amount of time and probably money by hiring a professional. This can either be to design and run your show, program your show, or just help set things up for you. What’s “worth it” to you will depend on your expectations and timeframe, having someone in person to teach you can work wonders. Hope this helps!