[Problem] SmartThings + Arduino - SmartThing Shield

Hi,
I am really new with SmartThing but I have a lot of experience with arduino. I would like to do a project with one temp sensor and a fan but I am a little blocked.
I think that with a SmartThing Shield it would be much easier, but I havent got this Shield.

I can turn on the fan from my phone without any problem, but I dont know what to do to send temp data from arduino to SmartThing Cloud.

Can someone help me?

Thanks…

P.S. Actually I connect my arduino with a xbee module directly. Rx->Dout; Tx->Din; 3.3->Vcc; gnd->gnd