The first step is to have a code for your desired color (HEX is best)
You can do this by:
Using google color picker or any other color picker online (you can also copy the code from a website where it says the exact color you're looking for)
in this image it shows HSL (our target format) but sometimes you can't access it (eg. getting it from a different website)

Next step is to convert your color to HSL (this format is used in Brick Rigs)

Now that you have the color code, we need to convert it into HSL. To do this go to any website ( this one is easy to use https://imagecolorpicker.com/color-code/38b09d), and paste in your color code
After you pasted in your original color click on the arrows until HSL shows up

Now that you got your color into HSL format, let's put it on our creation in the game.

HSL stands for Hue, Saturation and Lightness. We can see these properties in Brick Rigs
To insert our color here you just have to copy the H value from your desired color into the H property in Brick Rigs, do the same for S and L is V in Brick Rigs

If you did all of the steps correctly, you should have your desired color in the game
Note: the color might look different because you use a material that changes the color drastically (tungsten, copper, gold, chrome or glow) To know if the color is correct, compare the original color to the one in the little window in the color selector in game