First, access the Vimeo site, locate the video you'd like to use, and then click the Share button located on the video.
Next, go to the Embed field and copy the embed code.
Now that you've got the embed code copied, the rest of the work occurs in RoboHelp. Go ahead and open a RoboHelp topic, switch to HTML mode, and then paste the embed code in the topic as shown below.
Lastly, you'll need to edit the HTML just a bit. In the src attribute, type https: in front of the url.
Save the topic, generate the layout, and open the topic in your browser to see the embedded video.
Note: Vimeo includes a hyperlink with a description below the video. Retain this link unless you have the correct license for removing it.