WS2812B beginner

i have taken on a challenge and need a bit of help. i am repairing a fiber optic village Christmas decorations that my gran bought 10 years ago, it used to run on standard leds in the back but they broke some years ago and where binned, i have designed and 3d printed holders for WS2812B leds, i am using 4 groups of 4 leds, the fiber optic strands are split into 2 sections over 2 building so 4 sections in total, 2 for the roof and 2 for the interior. what i need it to write code to make 8 of the leds white and twinkle for the 2 roofs, and the other 8 to color shit, rainbow flash or anything really as long as the color changes. the way they are wired its 4 colored 8 white 4 colored, 16 in total, my problem is ive looked at the led code generators and they cant program this. nor do i have the programming skills to do this on my own, if anyone has any tips or pointers for a way to do this i would be very thankful as my gran would be over the moon to see her old decoration up and working again as it has a lot of sentimental value to her and the family

again leds 1-4 will have color shift or some rainbow-like effect. 5-8 and 9-12 will be white with some kind if twinkle or shimmer and 13-16 will be like the first 4

Sounds like a cool christmas present. You can purchase leds that change colors for a relative low price. A quick check on eBay gave me this: 20 x LED 5mm RGB Slow Auto Change Red Green Blue Ultra Bright LEDs Light RC Car. I think with a little more research you can find ones that will do the twinkle for you and you end up without the need for any code.

For an example of doing this see reply #2 in https://forum.arduino.cc/index.php?topic=715432.0