First 6 weeks will be very hard but it gets easier!!!!
I have 18 months 4 days between my boys.

DS1 loves DS2 so much and wants to hold him and give him kisses all the time so I sit him on couch next to me and lay DS2 on his knee.

When feed time for DS2, I always make sure DS1 water cup is full and if getting close to a meal time, I would let DS2 cry for a short time while i get DS1 sandwich made or what ever so he can sit in high chair and eat and watch tv.

DVD's are your friend,

I had a bag with some books and small toys for feed times. DS1 also brings me things over like the shapo and I will open it and turn to shape for him to put them in.

Keep older childs routineas much as possible and involve him in the care of newborn as much as possible.

Good luck