combineChildren

hi, i read that combining meshes with the same texture will bring better performance in the game,
and i read that this can be done with a combineChildren script. However, im not sure how to implement this script
so that the objects i want to combine, gets combined. Could anyone please help me with this?

Simply drop the CombineChildren script from the Standard Assets Scripts onto the parent of the objects you want to combine.

thank you:)