Recover Library/Photos from Backup?

I re-installed Win7 last week, after performing a complete back-up to an external drive.

I have re-installed LR5, and now would like to recover the libraries/photos from that back-up.  After a couple attempts, it is clear I have no clue what to do.

Here is what I have (copied to a folder on my desktop):

From Back-Up

============================

1.  Lightroom 4 Catalog.lrcat

2.  Lightroom 4 Catalog Previews.lrdata

3.  Lightroom 5 Catalog.lrcat

4.  Lightroom 5 Catalog Previews.lrdata

Note:  I have added some photos to the current LR5 catalog

Any suggestions to complete this task?

Thanks!

Mark