It is assumed that you have already activated your AWS account.
Allocating static IP address
Now, you can access Plesk admin dashboard, which is covered in an earlier article post written for Lightsail instance here: Plesk Hosting Stack on Ubuntu: 3 websites under one instance with plans starting 5$ per month on Amazon Lightsail and a demo of migration with free Migrate Guru plugin. The Plesk admin dashboard remains the same irrespective of being launched either on Lightsail or EC2 as for this demo.