What the diffence between “不”and “没”?

To say it simply
不 is used to negate present or future verbs like : 我不吃 means I don't eat or i wont eat
没 is use to negate past verbs like: 我没吃 means i didnt eat
Note: 没=没有 so you can say 我没有吃 also means i didnt eat
For continuous verbs we also use 没 to negate for example: 我在吃饭 becomes 我没（在）吃饭/我没吃饭 which means im not eating

昨天你喝咖啡了吗？--我没喝。
你喝咖啡吗？--我不喝。
明天早上你想喝咖啡吗？--我不想喝。

簡單來說，不：可以用不喝咖啡，不吃糖果，用在你不做這些事。沒：沒喝過咖啡，沒有吃過糖，你沒有做這些事。