Excel VBA - Change cell color based on value smaller or biger

I found some similar answers but i have no idea of VB and so i thought i could ask if someone can write this code for me... :)

What i need is to check the entire sheet and if value is less than 40000 to fill the cell with green colour . If the value is bigger than 54000 to fill it with green..or else to fill with white

can someone help me , or write the code?... :DD