[v8] Sale_quotation_products no button or clue to add selected products in search form into order lines

[bunhin]

I install sale_quotation_products, then go to sales --> quotation -->create, the quotation form displayed with "search product" button displayed in the button, fill customer information for quotation then i click search products button -->products displayed --> i click in the box to select products to add into quotation, but there is no button or clue how to add it into order lines, i also try with input number in the first column, but still now clue how to add into order lines

is it bug or expected behavior? then how to add the product into order lines?