You can publish your app as specifically made for smartphone, or for tablet too.
Tablet Layout uses the same settings of the smartphone.
Setting tablet compatibility (publication)
Go to your dashboard and click on the Promote Tab:
Then click on Publish on Stores from the left hand side menu:
Choose the app market platform where you wish to publish your App:
click on Download Native App:
Select whether you want your App to be compatible only with Smartphone format or not by flagging the box:
You will find the box flagged when you get to this point. If you unflag it a reminder will appear underneath:
The same thing applies if you wish to have us publish the App on your behalf.