Day one with Marley and the new pup Jasmin

[MarleyPyr]

Hi BPO'ers...We got our new pup Jasmin yesterday and she is cute as ever! We introduced her and Marley on neutral ground and it went ok. Marley doesn't really want much to do with her though which I think is common? anyway there have been a couple of growls from Marley in supervised play time and this morning there was a growl followed by a snap (not a bite) when the pup sniffed one of Marleys toys on the lawn.
From what I have read, I am supposed to let this happen? At what point is it correction time for Marley or Jasmin?