I am doing a final essay for my anthropology class and the question is "how humans disperse into the new world

[ready to pop]

Basically how, after evolving in Africa, did they end up spreading out into the new world, what were the routes that were taken, did they utilize boats, did the continents break apart???? AHHHHH I just finished a six page paper on modern homo sapiens and my mind is a blank!! Any help would be really awesome, thank you!