Concept of Object Repository (OR)

Add Objects:

Resources --> Object Repository (Ctrl+R) --> Objects --> Add Objects to Local --> Choose the Auto (or) Object --> All object Type

By doing above operations in Resources menu in QTP objects are been added                         
Save OR:

OR - Window --> Export Local Object -->  File Name

By doing above operations in Object Repository menu under Resources in QTP OR is saved.

Associate Repository:

Resources --> Associate Repository --> (+) click --> Choose tsr file --> Available Action --> Action 1 -->   Associate Action --> OK

By doing above operations the created objects (.tsr) are been added to the Associate Repository

(or)

we can add the path of the .tsr file which indicates the repository where it get stored

RepositoriesCollection.Add "C:\Program Files (x86)\HP\QuickTest Professional\TSR\flight.tsr"

Systemutil.Run(""C:\Program Files (x86)\HP\QuickTest Professional\samples\flight\app\flight4b.exe")

Dialog("Login").Active
Dialog("Login").WinEdit("Agent Name:").Set "admin"
Dialog("Login").WinEdit("Password:").Set "mercury"
Dialog("Login").WinButton("OK").Click
Window("Flight Reservation").Close

So, as per the above script if the qtp play backs these scripts, even if the objects are not assigned to associate repository (RepositoriesCollection.Add "C:\Program Files (x86)\HP\QuickTest Professional\TSR\flight.tsr") the given script will bring the stored objects from the targeted path.