How can I view or FTP into my WordPress site hosted on AWS?

Yes this question probably belongs in an AWS SO somewhere.
But yes you’re on the right track, you’d most likely look under EC2 for “instances”
If there’s only one instance, your life will be easier.
Find the ip address bound to the instance in question.
I would have to guess that both:

• FTP is not enabled on the server,
• FTP is not allowed by AWS firewall policy,

And you will have better success using SFTP but will still probably have some learning to do if the access permissions aren’t enabled, you’ll need to add a new firewall rule as well as get hold of an access key (pem file).

When I connect from Linux to AWS with SFTP, this is the command used:

sftp -o "IdentityFile=my-aws-xyz.pem" [email protected] 

(Replace X,Y, Z with your values)