Experts usually recommend that newbies buy these types of helicopters and fly them. While you are getting a cheaper RC helicopter that won't be as flexible as a more expensive model, you'll get a lot more stability in the air when you fly a coaxial RC helicopter, and that's why it's a good beginner model.
Connecting Using a 3-Point Swashplate The diagrams below outline the servo connections to the SK 720 using 3- and 4-point swashplates. When using a three point swashplate, you can mount the centre servo in front or behind the left and right servos Figure 3 - Connecting the SK 720 to a 3-point swashplate, with the centre servo mounted aft . T-Rex 450L reverses the common impression people have on T-Rex 450, with material integration technology utilized on side frame design, and has features previously found only on larger models, such as battery mounting rails, top mounted motor, 700E DFC type main bearing block with integrated servo mounts, forming striking resemblances to larger ...6. Module 2 (Electric RC Helicopter Types) contains Chapters 7 - 10; Module 3 (Learning to Fly an RC Helicopter) contains Chapters 11 - 15; and Module 4 (Modifications) is made up of Chapters 16 - 21. The guidelines provided in this book will help you to overcome the initial difficulties that most hobbyists encounter.
this video will help you understand what servos are and what a swash plate is and how they work together.