Hi Danahyousef!
As mentioned in the course requirements you need an external wireless adapter for the cracking lectures 11 to 28, you can do everything else without one though (from lecture 30 and on), just make sure you set Kali to use a Nat Network as shown in lecture 5 and skip the part where I add my external wireless card.
The built in card is not good for hacking, you need a powerful card that supports monitor mode and packet injection, I recommend anything with an Atheros or RTL8812AU chipset.
Checkout the adapters on the following link, they all support monitor mode and packet injection:
https://www.zsecurity.org/shop​

If you’re not sure which one to get the checkout the adapters video in the resources of lecture 11, here is a link to it anyway:
https://www.youtube.com/watch?v=0lqRZ3MWPXY​​

Thanks!
Diego