Time machine software....I think?

I just finished transferring info from an old mac to my laptop.  I had to initalize my time machine to transfer info from it.  Now my Macbook pro will not recognize my time machine.  To top it all off in our recent move, all my back up discs have gone MIA.  Any ideas how i can intialize this to my laptop?

Which WD external model you are using?

My Passport Studio, My Book Studio, My Book Essential…

How long have you been using it?

Have you been using WD external drive with a windows machine?

If right now, you are trying to initialize it with your new laptop, it would re-format the drive.

All data you have on the WD external drive will be lost.

Are you sure?