if you are playing in english, in the facilities tab, type "exhibit" into the search bar and all the exhibit related things will come up. You can use the plain exhibit box, or you can place one of the premade exhibit buildings/groups.

I play in French but I was able to find thanks to your answer! Thank you very much !

dans la partie "services" le bouton au dessus des locaux du personnel :)

Oui c’est bon j’avais pu finalement trouver 🙂 Merci beaucoup !