Best answer
Use the comment trigger, then make the private reply your first action and the public reply your second.
The order matters. The private reply is the thing that opens the DM thread, and Meta allows exactly one private reply per comment, so it has to be the action carrying your link. The public reply is the visible comment under the post. It is optional, but it is worth adding, because people scrolling the comments see that something happened.
The build:
- Trigger: comment on your Instagram account. If this is for one launch, set the post filter, otherwise an old post can start firing months later.
- Keyword: add the word people are told to comment, then pick the match mode on purpose. Contains catches "LINK please" and "send the link". Equals fires only on exactly "LINK". There are five modes and no fuzzy matching, so "lnk" will not match anything.
- Action one, private reply: your message plus a button. A button gets tapped more than a bare URL and it keeps the link out of the text.
- Action two, public reply: write two or three variations so the comments do not read as a wall of the same sentence.
Two things to know before you publish. Meta allows the private reply only within seven days of the comment, so a reply to a very old comment fails rather than sends. And if the person does not follow you, the DM lands in their Requests folder rather than their Inbox. That is platform behaviour, not a delivery failure, and it is the usual reason a creator thinks the automation did not run.
The Playbook: Comment-to-DM article has the same build with screenshots.