That was me. You have to find a place to host your video. I just used my Google Drive. It's not an ideal option but I had difficulty finding a place to host a video. YouTube is out because they consider it porn, which it clearly isn't. A still image is much easier as there are plenty of sites to host still images. Once the image or video is uploaded to a host you just send a link to the video or image. How you do that varies by hosting site. There is no provision, at least there wasn't last time I checked, to host a video on this site. I can give more specific advice if I know what you want to post or share. You can check out
https://imgbb.com/. I don't claim this is the best hosting site for images but it does work. I don't think you can do videos but I'm not sure.
What is it that you're having difficulties with?