(refer Putty Guide available at https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/connect-linux-inst-from-windows.html for details on how to connect using putty/ssh).
Open putty, paste the IP address and browse your private key you downloaded while deploying the VM, by going to SSH- >Auth->Credentials , click on Open.
Login as ubuntu user.
Update the password of ubuntu user using below command :
sudo passwd ubuntu
Once ubuntu user password is set, access the GUI environment using RDP on Windows machine or Remmina on Linux machine.
Copy the Public IP of the VM and paste it in the RDP. Login with ubuntu user and its password.
To access the DifyAI web interface , open your browser and copy paste the public IP of the VM as https://public_ip_of_vm. Make sure to use https in the URL.