Here are Facebook's instructions for downloading your data. Be sure to select JSON data format, not HTML. For the purposes of using this tool, you only need to select the data that will be used, but you can also select your entire data thing to keep things simple. This tool will transform posts and media, so it needs these items:
It helps to keep your site clean of plugins that you don't need anymore. If you do not intend on doing anymore data imports in the near future, deactivate and delete this plugin.
These are web page views of your chat history with each person and are packaged in a downloadable compressed zip file.
You can get an indication of what's in your chat logs by viewing the table. You can sort by Title, which is the Facebook user you chatted with, or you can sort by Message Count.
In order to download the Chat Logs (in a compressed zip file), you will need to purchase the Messenger Chat History option. This runs a program that parses your DM records, puts them in easy to read HTML files, and compresses them into a zip file for easy download.
To deter privacy abuse, we are not making chat logs available to import into WordPress. Instead, they will be available as HTML files in a zip file that you can download. You will then be able to open the files on your local computer.
The title column has links showing an indication of the user(s) you chatted with. The File Count column gives you an indication of how many photos or videos you had in that that DM conversation.
When you click on a link in the Title column, you'll see a familiar table with the same form options as Posts. Instead of seeing "Create Post" buttons, you see "Create Gallery" buttons. When click the Create Gallery button, it will upload the pictures or videos in that row and create a post with that media included. A thumbnail preview collage will be created for the blog roll preview of that gallery post if there are multiple images. The "Upload Individual File" button just uploads the individual file to your media library and doesn't create a blog post.
Messenger photos and videos are available as an option to import media into WordPress. You often share these memories directly with your friends, but you don't share them on your timeline. When you upload to WordPress, they aren't turned into posts in a blog, but rather kept in your WordPress media library. You can then share them in blog posts that you then create. Please use discretion and don't abuse this feature.