How can i build a list for the player to choose from?

I need to know how can i build a list inside the game As the list of buildings in strategy games, or as the friends list in SimCity .. !!

 

look into arrays or java list's
start here:
http://docs.unity3d.com/ScriptReference/Array.html

 

Thanks Jmanpie, Do you think i have to use OnGui to show this array to the player !

 

so what can i use to build this list !

 

In the script i would simply go the way that Jmanpie has suggested. Have a look at arrays or dynamic lists.

Everything else is up to your own desire and design, how you want to present the selectable items to your users.
You could offer GUI-buttons to click on (text only, with textures, or whatsoever), you could use planes/sprites as buttons or even meshes which you can preview/rotate and click on.

You've got total freedom there, that's a matter of design/usability.