If you want to add a new item to the craft menu so you can craft it you need to open the data table DT_Craft. In this data table duplicate any row. Here you need to set the item you will get as a result of the craft. 

Open Result (1) variable and initialize the item. Make sure you have this item in the items data table (use 1.6 if you need to know how to add an item to the items data table). You can also set the amount of items you will get. 

Now you need to initialize items (2) you need to have to craft the result item. The process is the same. You need to select the items from the items data table.  You can also set the amount of items you need to have to craft the item.

If you don’t want to use an icon out of the items data table you can set the unique one. (3)