Supports in MatterControl?

Hey folks I just got my new ROBO 3D R1 Plus. Im have done a few prints so far and everything has turned out great. But up to this point I have not needed any supports. I decided to make a shard for the extruder which will need supports. I saw in the setting that it will make its own supports and its checked off. But how do I activate it so it adds it to the item before it prints? Right now I basically have been adding things then hitting print. Is there a step in between that I'm missing?

Hey thanks in advance guys.

 

With support enabled you need to reslice the object. You can preview the G-code to be sure it added it.