Board Game Arena

Quick question, in this game I have played my "Den builder" occupation card and it's sitting there, I'd like to use its effects. How do I do that? I can't figure out what to click.

https://boardgamearena.com/10/agricola?table=479703810#

When you renovate to clay or stone, you will then have the option on your turn to pay the price (1 grain and 2 food) in order to get the effect of the card.

Thanks was being idiot