Yesss of course you can. There are a lot of certification courses available which start by explaining the basic concepts. Since you've done BCA, I'm assuming you already have a faint idea. The course will cover almost everything and is perfect for beginners.
Amazon also has its own course as well which is pretty amazing. There are other e-learning companies like udemy, intellipaat, linuxacademy, etc.
Check out Edureka's AWS Architect Course. Edureka’s AWS Architect Certification Training is curated by industry professionals as per the industry requirements and demands. It will help you prepare for the AWS Certified Solutions Architect (CSA) - Associate Exam. With Edureka's instructor-led sessions, you will be able to effectively deploy secure and robust applications on AWS. The course will help you identify the appropriate AWS service based on data, compute or security requirements.
You can check the one appropriate for you and start the course.
All the best :)