Facebook -Sharing-No images

Hi, New to the forum, and decided to join because I cannot find the answer I need. I am not as technical as most when it comes to understanding why things don’t work.
My problem is: When I am on my webpage and I post a video from youtube on it by embeding the code, When I go to share it to facebook it will not post a photo with the description or if it does post a photo it is one that it grabbed randomly from my site. I have tried to upload photos and link them to the video, to no avail. I tried using the youtube link, and the embed feature. nothing. I have tried meta tags with OG format.
I just don’t get why this is so difficult? I have downloaded every social share plugin (to which most are the same)
I guess my question is. If you are running a wordpress site and use share buttons what are the steps you have done to make your share button grab the content that you want and post it to facebook. Someone must have done this. I see it working on the web on many different sites all the time. If someone who is much more talented than me could design/figure this out I would be over the moon. Many thanks!