You can use any ssh software like putty or WinSCP. Yes, you will have to download this separately. Here is the putty download link for your reference.
A thumb of rule for all Linux OS on AWS is as follows:
Username will be "ubuntu" in the case of Ubuntu OS, it will be "ec2-user" for every other Linux OS on AWS.
Please check your security groups, and check if port 80 is open. You will also have to check if apache2 is running on the server after installation.
You can run apache2 using the following command:
sudo service httpd start
Hope this helps! For more information, refer to this AWS Tutorial