First, click to select a table item on the left listbox, program list all fields on right listbox, click to select a field, click Field value button, the program will show Field Value Editor window, list all value of this field, you can add/delete/edit these value.

This is not an editor for common extracted database field. It is only used for field that would be inserted into URL, see the following:

You want to extract a URL when key equal A/B/D/F:
http://www.example.com/list.php?key=A/B/D/F
You don't need to extract one by one, you can first create a table with only one field, then click field value button, then input A/B/D/F, one per line, click OK to save. OK, now you can write the URL like this:
http://www.example.com/list.php?key=<FIELD:T5,F33/>(<FIELD:T5,F33/> is the field including A/B/D/F)