...
To add an inventory item, click the Add or Pick button (refer to Using the pick operation). In the Item column, select an item from the Items list or create a new item. For more details, refer to Items. Alternatively, you can import the list of items with all the details from an Excel document. For this, click the 
button on the table toolbar and follow the step-by-step instructions in the appeared window. The imported list can be edited in the Administration module.
...
The Characteristic column is available if the Enable Item Characteristics option is selected on the Administration > Settings > Purchasing and Warehouses form. In this column, you can specify additional properties of each purchased item if the Use Characteristics option is selected for the item in its master record (see Items).
In the Quantity column, you can specify the item quantity and in the Unit column, you can select an UOM for the item if the Multiple UOMs per Item option is selected on the Administration > Settings > Purchasing and Warehouses form.
...
For other button descriptions, see Document Toolbar.