Your message is a bit confusing to me because Villagers don't use cubes. If I misunderstood you, please clarify!
There are Villagers, online they look like this (when you have 2 Villagers):
You can, in your Action phase, click on that icon and this converts 1 Villager to 1 Action. But you normally never need to do this, because when you have no Actions left but Villagers (and Action cards in hand), the game will simply allow you to continue playing Action cards and automatically use Villagers for that. It uses some red in the text to warn you that now you are using up Villagers, and the card outline is blue instead of the normal green:
Projects use cubes. You get as many as Projects are in the game (max: 2). In the beginning they are in each player's info box (here together with Villagers):
Once you've bought a project, they move to the project to indicate that you bought it and it now "works" for you:
I hope this answered your question. If you had something else in mind, please clarify.