Which version of Beersmith do you have? 1.4 or 2.0 In Ver 1.xx you just go to the top menu bar and under 'insert' pick the ingredient type you want to add and the enter your details. In 2.0 click the 'Ingredients' tab and then select the type of ingredient you would like to view. A list will open up and a new menu bar, on that menu bar should be an 'Add xxx' button. Press the button and add away. Finding the info for your ingredient can be a little tricky. For pumpkin, I have 3.0 SRM, 1.005 10% for the yield.
Draft 1: Belgian Chocolate Stout
Draft 2: Belgian Wit
Draft 3: Double IPA
Primary 1: Irish Red Ale
Primary 2: Weizen
On Deck: Imperial Stout, Berry Wheat