Hiya (sorry I've been offline - sickness and work busy!) - I've definitely done borders in the past but it has been quite a while since I last went to DL and used their photopass. From memory, you just selected the photo and on the right hand side of the screen all the borders that were available would appear and you could just scroll through them and apply them.
But like I said, it has been a while since I've used the system so maybe they aren't available now?
Good luck Karen.
DLR: 2005, 2006, 2009, 2011, 2012, 2013, 2015
HKDL: 2006 (Mar & Sept), 2011 (Apr & Dec), 2014
TDR: 2008, 2010, 2017
WDW: 2006, 2013 (Mar & Sept), 2016
DCL: 2013, 2015 (Alaska & Hawaii)