You can allow your viewer to visit any website just by tapping the video. To add clickable external link buttons within your adventr, first, drag an “External Link” tile onto the canvas.

Then hover over the clip you'd like to create the link from, and click the Arrow Icon. Then connect that to the External Link tile by clicking on it. A line will be drawn between them. 

Then click the Pencil Icon on the External Link tile to edit the link. You'll be able to change the URL.

Edit the video you are linking from to customize the appearance of the button that opens the link.