So, to begin, take your Server and take a look. What do you see? Depending on the Model, it'll all be similar, yet have differences between the two. Both models have a removeable Faceplate and Side Panel. The Faceplate will be removeable on the front at the top parallel to the front IO and system Info Monitor.

Just like a regular desktop, the Chassis Side Panel is able to be removed to access the main Cavity and the rest of the internal Components. Simple as that.

For the Hotswappable Model, remove the Faceplate. But for the Internal Sled Model, there is no way to access from removing the Faceplate because it is only accessible through the Internal Component Bay.