Greetings,

You should first start learning basics of cloud computing.Buy a online course available in various educational website like Udemy,Coursera and much more.

Try to get in hand experience of Cloud Computing by Cloud Practitioner certificate.

AWShas three levels of certification. 
There’s the foundational level, the associate level and professional level certification.

Now, if you’re a beginner, (like a complete newbie to AWS) I suggest that you start with the Cloud Practitioner certification. It’s probably the easiest among the certifications you can choose from. They’re optional, but give you the much needed insight into the various domains and services that AWS covers. This certification costs $100.

Hello aspirant,

To become an Amazon Web Services engineer, you need to have extensive knowledge of cloud computing and related topics.

First of all join an engineering college with CSE branch if you have not joined any college yet as many subjects are covered in CSE branch. Then focus on given subjects - 

Data science

Machine learning

IOT

Cloud Computing

Ethical Hacking

Besides there are many certification as well as NPTEL courses available for cloud computing.

Best of luck.