You heard wrong. The manual is not to long to go through.
It's OK to use the camera right away, but the camera is a tool and the user's manual tells you about every camera control, feature, and function your new camera and lens (tool) has. It's likely you've not used any consumer electronics as complicated to use as your new camera will be, unless you leave it in AUTO mode all the time.
You can bet advanced amateur and professional photographers read their user's manuals.
You don't need to read the entire manual at one sitting, but you need to read it all the first few days you have the camera. Actually you need to read the manual several times because no one is able to remember that is in it after just one read. A key to using the manual is becoming familiar with how it is organized so you can look up stuff up easier.
Since it's a user's manual it's not a fun read, but a dry read. The first part of the manual shows you how all the external camera controls, ports, switches, button, etc are all laid out.
Once you get your camera you'll need to charge the battery. Start reading the manual and finding the external controls while the battery charges. When you read the manual, have your camera right there so you can look at it as you read.
