Tasks for AWS can be installed and upgraded like any other regular app via the Universal Plugin Manager (UPM) (see Managing apps for details):
Log into your Bamboo instance as an administrator.
Go to Administration > Apps. The Manage apps screen loads.
Click Find new apps from the left-hand side of the page.
Locate Tasks for AWS via search. The appropriate app version appears in the search results.
Click Try free to begin a new trial or Buy now to purchase a license for Tasks for AWS. You'll be prompted to log into My Atlassian if you're logged out. Tasks for AWS begins to download.
Enter your information and click Generate license when redirected to My Atlassian.
Click Apply license. If you're using an older version of UPM, you can copy and paste the license into your Bamboo instance.