Select the word that you want to link and press the link button:
A window will pop up, and you can insert your URL there:
To add an image select the image button on top of your question:
Paste the image link on the popup. It will be displayed like this in tour chatbot:
TIP: To find the image address, right-click on the image that you want to link here and choose "Copy image address"
To add gifs and videos, you must use the HTML button:
Then, you have to paste your embedded code (you can find it in a lot of apps, like Youtube or Giphy) on the popup
TIP: Change the embedded code so the video or gif has width="190" height="105", this way, you'll be sure it will fit in the question box