IGMsg uses the official Instagram API, so the first step is connecting your Instagram professional account (Business or Creator). It takes about a minute.
Switch to a professional account
In the Instagram app, go to Settings → Account type and tools → Switch to professional account and choose Business or Creator. This is required by Instagram for any automation and is free.
Link an Instagram Page
Instagram requires your professional account to be linked to an Instagram Page. In Instagram, open Settings → Accounts Center and link (or create) a Page. You will not need to post to it.
Click Connect in IGMsg
In IGMsg, open Accounts from the sidebar and click Connect Instagram. You will be sent to Instagram to authorize IGMsg, then returned to your dashboard.
Approve the permissions
Approve the requested permissions (manage messages and comments). These let IGMsg read the comments that trigger your automations and send the DM replies. You can revoke access any time from Instagram settings.