How to send replies after auto-DMs

I have set auto-dm links from comments on specific keywords which is working fine and they receive the link via DM,, but I also then want manychat to send a reply back to the user with a message to their original message, informing them that I have now sent them  the link, and they should check their DMs.  I cannot see in the help files how to automate this second part of the requirement, if anyone can help that would be great!