I'm not exactly sure what you're trying to do but here are a few suggestions:
1. From the sky object you can change the rendering style of the sky, ambient, blurry, or simply set it to a solid color if you don't want to see the sky.
2. You can also add a backdrop image (scene > add object > backdrop) which will allow you to replace the background with a custom image.
3. From the render options you can set up a transparent background, and then composite the video in video editing software onto a custom background as well. Though #2 is generally easier unless you are trying to composite it over another video.
Replies
1. From the sky object you can change the rendering style of the sky, ambient, blurry, or simply set it to a solid color if you don't want to see the sky.
2. You can also add a backdrop image (scene > add object > backdrop) which will allow you to replace the background with a custom image.
3. From the render options you can set up a transparent background, and then composite the video in video editing software onto a custom background as well. Though #2 is generally easier unless you are trying to composite it over another video.