Click the work button to earn Importance, then spend Importance on upgrades that earn Importance per click and Importance per second. It is the office ladder as a clicker, and the buy 1 and buy 10 buttons sit side by side from the start so you are never stuck buying one at a time.
The interface is in Spanish, and enough of it is unlabelled that you will be reading numbers rather than words. Nothing about it is difficult to follow if you have played one of these before, but going in cold without the language is a rougher time than it needs to be.