[1.5.0.x] How to add product's Option?

How to add product's Option?

In the tab of "Option", there is a text input area and a "Add" button. But it is no use for clicking the "Add" button. How can i add an option for my product?

Thank you in advance for help.

Go to "catalog-option" and set up an option and its option value. For example, you can set up an option of "color", which has "white, black and red" values.
Then in the tab of "option", input "color" in the text input area and the option " color" will come out, click to select it and all the values will come out then. You just need to select what value you want.