How to make a cinematic game trailer in Unreal?

Does anyone know the steps/items needed? I want my trailer to include my main character walking and talking in it.

This can be quite an undertaking;

Figure out your end goal:
Storyboard the sequence**
-this will drive how many and what animations you need.
-make those animations

-script, get a writer or write it out, how long is it? how many lines are there? VO or silent?

Where is it?
Create an asset list of what you need - can you use free marketplace assets? (I would start there for a simple scene blockout)

Matinee or Sequencer?
Block out the storyboard, camera angles and shots.

There is more to consider - but start with those.