Log into your Confluence instance as an admin.
Click the admin dropdown and choose Add-ons. The Manage add-ons screen loads.
Click Find new apps or Find new add-ons from the left-hand side of the page.
Locate Advanced Excerpts (Micro Templates) via search. Results include app versions compatible with your Confluence instance.
Click Install to download and install your app.
You're all set! Click Close in the Installed and ready to go dialog.