I went to google and typed "How to build a megatree". i got 1,170,000 results. There are a lot of tutorials on the web on individual peoples websites, on Christmas forums, commercial sites, etc.
But if you have no experience at all with doing animated lighting you need to get some basic information and some experience with basic animated lighting before taking on the mega tree task. Many of us have built a number of mega trees and have had them be epic failures because we did not know what we were doing at the time although we thought we did. Now (after doing this for 8 years) I have a rock solid megatree made up of 64 strings of LEDs and a Pixel tree created with 16 strands of RGB pixels. Next year I will be building a 2nd pixel tree. There are lots of decisions that have to be made, type of lights, how big, where are you going to put it, how are you going to power it, how are you going to electrically control it, how are you going to sequence it, what music do you what to use, what kind of materials to use, how much are you willing to spend.
Almost every Christmas forum I belong to have a lot of historical threads about mega tree building and recommendations about all the topics I listed above. I think you need to search a little harder and not just ask the question and expect a simple answer. There is lots of help available, but you need to be more specific about your skills and desires.