Q: How can I add a location to photos I previously had imported from my SLR in Photo as I used to be able to do in iPhoto?

I've just upgraded my iPhoto app to Photos and having a few teething problems In iPhoto I could add a location to photos I previously had imported from my SLR by using the information windows.  I can't do the same now my images are in my new Photos App Library.  Going to Metadata option gives little joy.  Wish to add locations to the imported images from my SLR to the new Photos App.  How can I go about doing this?

Go well,

blueeccles