To select a cover from your own video:
Once you have created a new post for Instagram, chosen the option to schedule a Reel, and uploaded your video, the option to add a cover will be enabled.
Hover over the video and you will see a button that says "Cover", click on it.
2. Choose the option Video Frame.
*Instagram does not support custom images, so the first frame of the video will be used instead.
3. Below the video you will see a bar, please use the cursor to select the part you want as the cover.
Remember that the selected fragment of your video must have the elements centered, respecting Instagram's safety margins. The image fragment you choose will be the one that will be seen in your grid.
4. Click on Save Thumbnail.
That's it! The fragment of the video you have chosen will be your cover.