If you want to upload a video you made, try uploading it to YouTube first and then embedding the YouTube link onto your tour. This will make streaming easier and you won't have to worry about file size limits.
Don't have a 360º camera?
Take a panorama photo with any smartphone and convert to a 360º image it at thinglink.com/pano-to-360
Check your viewing privacy recommendations so that your audience can view all of your material.
If you include images that you did not capture, make sure that the copyright allows use and include a credit. You can also reach out to the creator for permission.