Can you please provide the step by step procedure to install and configure the "Splunk app for AWS". seems the below document has high level info. We need to know where this app to installed (search node or indexer node) and what are all the requisition details to enable this app.
Everything you need is in the link you posted under "Installation and configuration".
To sum up:
Step 1. Install the Add-on - this could be in your Search Head or HeavyForwarder depending on your deployment. (it has its own instructions, also linked there)
Step 2. Configure the Add-on
Step 3. Install and configure the App