Final answer:
Employees need to download the Hootsuite Amplify app from the App Store to start using the platform for employee advocacy and content sharing.
Step-by-step explanation:
For employees to use Hootsuite Amplify, the correct first step they need to take is to download the Amplify app from the App Store (Option D). Hootsuite Amplify is an employee advocacy tool designed to allow employees to share approved brand content across their personal social networks. To start using it, employees simply need to install the app on their mobile devices. There is no initial requirement related to being added to a specific team within Hootsuite Organizations, having security clearance from an authorized Hootsuite representative, achieving a certain number of impressions, or finding content to upvote in the Content Library.