You can watch our tutorial or you can go through or documentation about select components :
Agilitest native manages SELECT components in HTML and combo boxes for desktop applications. This is necessary because these components have a graphical interface and a particular behavior: it is a matter of selecting one or more values from a drop-down list.

There are 3 possible options to select a value :

Index selection
The index corresponds to the position of the desired value in the drop-down list, starting from the top and beginning with 0.
Simply check the Index box and enter the desired value, obviously this index must not exceed the number of values proposed -1 otherwise no text will be selected.
Selection by text
In this case, the text will be selected if it corresponds to a possible option proposed by the SELECT.
This makes sure of the value used, but it still needs to be proposed.
Value selection
The value attribute is an additional value that is provided in the HTML code and that is related to the displayed text. This allows you to select a text, but not to retrieve the value.
Again, this value must be proposed for the corresponding text to be selected.