Distances multiple locations automatic calculation VBA

Hi Guys,

I have a question. I need to calculate the distances between multiple (german) factories and many many store adresses. To do this manually takes ages.. The disntaces are based on postcodes/villages and no coordinates.
I know I need a macro, and have seen some examples but I don't know how to get the macros running on my excel.

Could someone please help me?
And if you have a working formula (thanks!!), could you also describe the steps how to apply this to my sheet to get it running?

Thanks!!
PS: the sheet basically looks like the attached files