If you wish to add a title from the search results or only a few of them to the list, you will do well to work directly from the search results. There, you will find to the bottom right of every title a button entitled "Add to List". When you click on this, the title will be added to your list, and the very same button will display a different command: "delete from list". You can decide to undo the addition by clicking this button. The total number of list entries is conveyed in the right column.