To "put together" or merge MP4 content like this, you can use various tools and methods depending on your device: Recommended Tools for Merging MP4 Files

Search for your videos, long-press to select multiple files, tap the "+" symbol, and choose "Highlight video" to automatically combine them.

Use the Adobe MP4 Merger to upload clips, trim them as needed, and download the finished product without installing software.

Open the pre-installed Clipchamp app, import your video clips, and drag them onto the timeline. Ensure they touch (indicated by a purple line) to remove gaps before exporting as a single file.