Hacks and tips on sleeping alone!!

Ladies my toddler is 2 and I’m due in 2 months. I know please don’t judge I waited at the last minute but I need help my toddler has never fallen asleep alone since she was 6 months she sleeps on her own room but I must rock her until she goes to sleep. At nap time I still have to rock her to sleep as well. Since I will soon have a newborn and since I need to have a C-section again I need for her to learn to self soothe and fall asleep on her own, yes she wakes up multiple times at night to be put back to sleep still idk what to do but worry for my little girl. We have tried before but she just cries her eyes out and I feel terrible and give in. What can I do to make it somewhat easier for her? TIA