I've been discussing all of Amazon Web Services' key offerings in-depth, including EC2, S3, VPC, Volumes, EIP, Subnets, Gateways, Route53, Auto Scaling, ELB, RDS, DynamoDb, Redshift, Kinesis, and Video Transcoder. However, it is difficult and difficult to remember to go into detail on each issue from the AWS official documentation.
What are the patterns, rules, and sample tests I can use to thoroughly understand the topics?
Do I have to buy the question sets that many websites offer, or can I just use the ones that are offered for free?