Abdullah's answer is great. However, there's a tiny thing that I'd like to add since your question is specifically about Egyptian Arabic and not the standard form of Arabic. In Egyptian Arabic, we place "كان", and all its other variations and forms, in the same position in the sentence where one would place its equivalent in an English sentence. Consider for example the sentence that Abdullah mentioned: "the food was delicious", this would become "الأكل كان لذيذ" instead of "كان الأكل لذيذ" which would be the correct form in standard Arabic.

"كان" have many other different uses aside from indicating the past. "هيكون" for example translates to "will be" or "will have been" depending on the context.

1- In two  hours, your food will be cold: بعد ساعتين، أكلك هيكون برد

2- By next week, I will have paid my rent: الأسبوع اللي جي، هكون دفعت الايجار

Also, It's used with unreal/imaginary situations of the past and future:

1- If you had called me, I wouldn't have been late: لو [كنت] كلمتني، ماكنتش اتأخرت

2- If I had any time this week to help you, I would have (but I won't have any time): لو كان هيبقى عندي اي وقت الاسبوع ده، كنت هساعدك

Hope this helps. Best of luck :)

Everything Uzair said is correct, except that he explained it using MSA grammar rules. Colloquial Arabic doesn’t have case endings.

The most important thing you need to know is that كان is a verb that goes at the beginning of a sentence, and the sentence has to be a nominal sentence. If you don’t know the two types of sentences in Arabic (nominal and verbals sentences), you need to familiarize yourself with them before understanding how كان is used.

For example:

كان الأكل لذيذ

الأكل لذيذ is a nominal sentence. It has no verb. “The food [is] delicious.”

You add كان at the beginning and it becomes “The food was delicious.”