Flat nipples and massive boobs here too. I watched my friends just pop baby on easily and it was never like that for me. I had a gadget during pregnancy that was supposed to help with flat nipples but it was a gimmick!
An amazing midwife spent time with me when I was in bits with a 1 week old baby at the start of mastitis and changed everything for me. Without her, I never would have managed to breastfeed.
First, mum has to be comfy. Get yourself in a nice supportive position, where you can sit for a while. I used to put pillows around me, under each arm and on my lap. People would laugh but it made such a difference.
Then, I used to lay my son on the pillow in rugby ball position, so down along the pillow, with his body under my arm. You can hold baby's head then but the pillow should do most of the work.
Then she showed me how to manipulate the nipple a bit to give him something to grip, sort of rolling it. Then using one hand behind him to guide his head and the other to create a nipple shape, stuff it all in! Go again if you don't get a good latch the first time.
Sorry for the length of post but nobody else ever showed me this. And if I can help someone else, that would be great.
Having said that, I combined this with formula after the first few weeks and have no regrets - apart from how much I beat myself up! Breastfeeding is not always the easy natural way people portray and the pressure was/is enormous.
Mine are teenagers now and, as another poster said, among their peers, you absolutely cannot tell the formula and breast fed kids apart! Do whatever works OP!