@yangz2, I agree with @HAWK, it's beautiful.
I'm not a designer so take that for what it's worth. Anyone, please feel free to correct me.
At the start, instead of having, 'For many Students', I would put, 'For many students'. I consider students to be a common noun which means it should only be capitalised at the start of a sentence. Also, please note, I'm from Australia so perhaps some of what I have learnt might not apply to you e.g. American spelling is capitalized.
I agree with @HAWK, the first carousel is too fast for me. The second one was too fast as well. You might want to check all of them just in case.
I would put 'Cooking needs more time' rather than 'Cooking need more time'. Ah sorry I can't think of what the proper English rule is. But I think I'm right.
What do you think of splitting up the How it works section rather than have it in one paragraph? So I kindly suggest this as an alternative:
1) Several people form a group and order meal plans on CoCook platform.
2) Then, they receive the pre-portioned ingredients from a nearby grocery supplier and the recipes from the platform.
3) Each member takes a turn cooking and delivering meals once for the whole group. The simplified recipe would shorten the cooking time, and people would eat healthier.
I'm not an expert so I don't know if I'm supposed to be able to read the personas, customer journey map etc. However, I'm using Firefox and I can't read it. Perhaps, you might consider the ability to launch a larger image when the user clicks on those hard to read images.
I truly do not mean to be rude to you as I can't even speak or write in another language (okay maybe a little German). You are definitely more accomplished than I am. I also don't know how important spelling etc. is considering I pretty much understand what you are saying anyway. However, I would suggest perhaps finding someone to proof read your website for grammatical and spelling errors. We are all human and I think a lot of native English speakers can be challenged by the strange and wonderful rules of the English language as well. So perhaps, if you can find someone who has something like a proper Cambridge TEFL certification to check through your website, they might have a good eye for picking up errors.
I have to get going but I noticed the word, 'received' spelt as 'recieved'. Here's a rule that has helped me:
'I' before 'e' except after 'c'.
Oh and perhaps I shouldn't be putting those letters in ' '.
Overall, great job!