My 2 oldest are exactly 2 years (to within 3 days) of each other. Dc3 arrived 22 months after that - so I had 3 kids under 4 for a while!
My biggest help was the 'feeding box'
I had a box - a small cardboard box - and in it was :
pencils
paper
couple of fave books
small cuddly toy
jigsaw type puzzle suitable for 2 yo
photo book of family inc grandparents and new baby
snacks (nice things - eg fruit, raisins, breadsticks (dd1's fave) and a daily small sweet treat) replenished after every feed.
then - every time new baby neded a feed it was a treat! We would get outthe 'baby feeding box' and toddler would rummage in, have fun, eat snacks, read books with me, all whil e I was breastfeeding younger sibling.
It seriously worked for months as long as I was careful to rortate items about every week and keep snacks replenished! Its my top next child tip.
Just also wanted to say that you should line up hlp if you might need it. We found the jump from 1-2 harder than having the first, as dd1 was pretty demanding, turning 2, and you cnat get all the sleep you do with the first as you have a toddler to entertain!
Al the best!