If you are starting out with a brand new channel (as I am) then the option to add what YouTube now calls a "card’ to your videos is not possible. You need to have a website “approved” and thousands of views before any rights to link from a video are granted.
Hence, why I have been looking for a way to embed a link into my own videos that can be posted on youtube.
But, I guess there is now way so will revert to editing videos and adding title over the video, etc.
Thanks for the help on this forum