Black hair.

(I was originally calling black peoples hair ethnic hair I googled it and I guess I shouldn't call it that. So if I'm wrong just let me know) Soo I'm in cosmetology school and I'm the only person there that knows how to do cornrows. Not even the instructors know how. I'm also white. I have someone coming to get cornrows and they are black.. I have no idea how to work on their hair. I cant find anything online. And I really dont want this person to feel bad if I dont know how to properly take care of their hair. I want them to have a good experience. So can someone please help me. What are the steps? When I work on straight hair I use this paste stuff to keep them neat. I part the hair clip it and put the paste on the roots. Is there anything else I should do? Or not do? And yes I know my school sucks for not educating themselves and students. At least I am trying. So please dont be rude. Also are there any youtubers anyone knows of that explain exactly how to take care of black hair? Or websites? Anything that could help me..