Introducing cats to dogs is tough -- especially when you have an over-eager puppy who is unfamiliar with the feline kind.
The next few months are going to be understandably stressful for your cats. Your best bet is to only allow them to see each other under controlled situations at first. You don't want your puppy bounding after your cats every time he or she sees them in an attempt to play. This will only cause your cats to have to 'hide out' at all times and it would be really unfair and stressful to them since they were there first.
I recommend having at least one room that is completely off limits to the puppy and can serve as a safe haven for the cats -- keep comforting things in there like scratch posts, bedding, and their food/water/litter area. Keep this area quiet and make it available to the cats at all times. It might help if you had a child gate handy so the cats can come and go as they please and this will also allow controlled contact with the puppy so he or she can 'see and not touch.'
Good luck.
They should come around eventually but it may take awhile.
