For my story the MC is black and I want to make sure I write her properly I don’t want to not include something that is important to culture.
Many authors have been called out recently about not writing the character correctly and I don’t want to be one of those people.
I just want to make sure that I am writing my story right and not disregarding their race if that makes sense 
You may need to specify… 
“Black” is a broad term. Not every black character is from the same culture, country, traditions, etc.
Yep.
Now, u need to think about what country your character is going to be from first. So, where is your character from? Then we can talk about culture, and other things.
Umm. I’m not really sure.
Cuz all Ik about my characters is that they are british
I’m not sure what country her parents are from.I didn’t really think
Oh okay, well I think you should do some research and choose his/her/their parents’ or grandparents’ backgrounds first and stem from there because honestly, the differences in black cultures, traditions, skin tones, hair textures, experiences, ethnicities etc would surprise you. 
Agreed!
How would I do that. Cuz I don’t really know much about black culture
You could research lists of black ethnicities.
If you have a specific area of the earth in mind, you could research black communities or ethnicities in those regions first. 
I guess the most typical is the continent of Africa, but there are different black communities everywhere — New Zealand, Australia, Papa New Guinea, Fiji (those are just a few examples) etc.
same way you would write a white charaterem except black, I think more you should think of what culture she lives in, like does she live in new york texas or maybe London, is she poor or rich, good parents bad parents,
I read a story not long ago where the author said MC was very poor, and then she lived in a giant house with a fireplace, own bedroom and walk in closet, that is not a poor person, no matter race,
there is a few think there is diffrent from white to black, like they dont just spend five minute brushing their hair, and maybe have diffrent out look on politick, maybe,
Is the Caribbean one as well??
I started writing my character the way I would a white character but I got a bit worried I wasn’t writing her correctly
As far as I know, there are Afro-Caribbean communities there meaning there are people with African and non-African ancestry.
I’m glad you’re taking the initiative to look further into it because a lot of black people do not experience the world the same way that white people do due to racism, systematic racism, systemic racism, prejudice, colonization, Eurocentric beauty standards etc.
How would I write an afro-caribbean person?
I want something that is truthful not something to what I think because Ik I will be wrong cuz im not apart of the culture
The best way to do that in your case would be to do as much research as you can on Afro-Caribbeans, the Caribbean, Africa, an African country that you want your character to have a connection to (because Africa is a continent filled with different countries) as well as reach out and ask if there is anyone who lives there or better yet, is an Afro-Caribbean themselves. 
https://www.wattpad.com/263561275-writing-poc-101-black-british-characters
Since you are talking about the character being british it will be different to others. Like the character might have developed an accent depending how long they have lived there there whole life, a few years etc
So they will have different concepts to other black people. I am from Scotland and a lot of us are white but I came across this girl on tik tok who grew up here and her accent is strong and she talks just like others from her area in the south. (she is black)
If you know where they are from it will help and if you want them to have developed the slang or if they have their own depending where they are from.
I have linked something I hope will be helpful, I don’t know if the link works.
I’m think that she was born there and her parents came over to england when they were children cuz that’s when their parentsmoved(grandparents)
I’m not sure if that would be correct. But I hope it is
Everyone has a different story so it could very well be. Think about why they moved, it might change how they come across to other people.
Okay! Thank you