You can start adding products by clicking the "New" button under the "Products" tab of the Sales Opportunity.
After clicking the "New" button, you must select "Product" from the Window or type "Reference Name".
Since the sales opportunity product may be a new product that does not exist in the system, you can use a reference name for the product.
Unit
"Unit of Measure Selection for Product"
If you have selected a product from the window and defined more than one Unit of Measure as the main unit of that product: you can select one of the units you defined in the container information from the drop-down box.
If you have defined only the main unit of the product, you must use it.