Steps to create Hexagon Background
Use Effect > Disort & Transform > Transform.
Preview on, scale percentage in minus.
Scale Horizontal and Vertical both 88%, Angle -5, Approx 18 Copies.
Select object and use “Object > Expend Appearance”.
Select and use Shape builder tool.
Click on each part separately.
First we fill gradient in outer shape.
Fill colors according to your choice.
Select shape after leaving one and fill gradient.
Now select rest of the shapes for gradient.
Choose different color for contrast color combination.
Group all, Create a mask layer and use Object > Clipping Mask.