We usually only show one promo on the site, the one with the end date closest to now. As promos expire, then more distant end dates become visible. If you want a specific promo to be visible regardless of whether other promos are showing or not, then change the Display setting to “Always show this promo.”
If you wish to use a Canva design as a promo, then you have to get it’s embed link and paste it into the Promo Embed setting. This link can be found by opening the Canva editor for a given item, clicking on the Share button in the upper right corner of the editor, choosing More, choosing Embed, and then copying the “Smart embed link”. Note that Canva designs work best if you make sure that their height is evenly divisible into their width (600 x 200, for example). If there is a remainder when you divide height/width, then you may see black edges to the promos from time to time.
Alternatively, you can use any image from the WordPress media library as a promo. It is best to use an image that has at least 600 pixels of width so that the design will appear crisp on modern high density displays (like tablets and phones).
If you do not add an embed or an image, then the content of the promo page (like this text you are reading) will become the promo itself. Note that you should always repeat any important text from the promos on the promo page, since this text will always be used to help those with disabilities understand the promo.
Usually you will want to turn the promo into a “button.” To do so, include either a Linked URL (which can point anywhere in the world) or a Linked Post (which only allows you to select items from this website). Either of these will transform the whole promo into a button, but in doing so they will also make it impossible to click on any links which may be contained in the promo itself.
Finally, the promos will appear anywhere you include Tenseg Promos block. This will typically be what you use in a sidebar or widget area.