I assume you're using your phone to post these. If it's Android and works the same way as mine, follow these steps:
1. Tap the white "Share" arrow under the video. On my phone this brings up a list of places to share the video, e.g. WhatsApp, Messages, Bluetooth etc.
2. Drag this list to the left and my last icon is an ellipsis (three dots) with the word "More" under it.
3. Tap "More" and I then get an option to "Copy URL". Tap this to copy the full youtube.com address rather than the youtu.be address that you normally get.
4. On HazzardNet, paste it into your post and hopefully the video will appear rather than the link.
If you're on a regular computer, just copy/paste the full URL from the address bar.
NB. Some videos, such as the Formula 1 videos that I post, cannot be embedded, so you'll still have to post them as a link.