Hey there Farhaan, welcome to the forums.
Your best bet is simply to take it slow. Don’t try to rush it, take your time with every bit of new information, and do not hesitate to look things up outside of Codecademy to help you along the way.
The MDN docs are a great resource to help you with that.
For every lesson that you don’t seem to fully understand, bits of code, etc., feel free to ask for help on here. We cannot simply help you “get it”, that’s really up to you, but if you try to complete the exercises yourself and then ask for help by showing us pieces of code, there are people on here that will be able to guide you and explain why certain things work a certain way, etc.
So keep at it, and best of luck to you, you got this!