Re adding images into Lightroom

Hi All,

This question has been asked before, I can see one or two answers to it but I don't really follow.

After replacing my operating system drive I now can no longer use Lightroom because the images are of course somewhere else.

I have the backup file which tells lightroom where my images used to be! So in what folder do I place my image files?? Lightroom of course puts images into yearly and monthly folders but i find it strange and frustrating that I cannot tell lightroom a file path for these.

So what is the file path for the image files?? is it in the "pictures folder"??

I launch the back up file and of course it will not work because it does not know where my images are located on this, what is in effect, a new pc