Create new product and choose product type "Gift Card".
This product has two new tabs in product edit page: Gift Card Options and Assign Gift Card Series.
Tab "Assign Gift Cards Series"
There is a list of available gift card’s series. You need to select gift card’s series and enter the gift card’s price.
Go to product inventory tab and set “Manage Stock” to “No”.
Other options works the same as simple product’s options.