Dog help

Ok so I have a 10 year old dog. She does get a little territorial with other dogs but we thought nothing of it . Tonight we brought a puppy home he has been bere for only 7 hours and it has been nothing but chaos. We have the puppy in a exercise pen in the living room so the 2 dogs can see each kther without either getting hurt . My dog just barks at the puppy nonstop and some of the barks sound aggressive and I’m scared to let the puppy out of the cage when she is around . Any suggestions . Tips , I’m about to lose my mind and it’s only day 1 . I’m also worried about not giving either enough attention . The puppy cries when I leave the room and my old dog likes attention and rubs