If you want to change the information, appearance or labels of an object, you need to select it, then open it's 'settings window'. This window is different depending on the type of object selected but the system knows and will show you the correct one. You can go about doing this in one of the following ways:
Hovering the mouse pointer over an object, so that the pointer changes to the image of a hand, then clicking the left mouse button will select an object.
Selecting an object's entry in the tree panel to the right of the main screen by pointing at it with the mouse pointer and clicking the mouse button also selects that object.
Once an object has been selected, a grey 'selection frame' will appear around it.
There are three methods of opening the 'settings window' for an object:
You can use the menu option 'Objects', then 'change object information and settings' as shown below:

You can click the right mouse button on the object in the tree panel and select 'Change details of this item' as below.

Or you can simply double-click the item on the map (press and release the left mouse button twice in quick succession).
Which ever way you choose, the appropriate window should appear. For more information on these windows see:
Objects can be copied either on the same phase or to another phase. You can do either of these by selecting the 'Objects' menu option (see below) or by right-clicking the selected object and selecting from the pop-up menu that appears :
If you want to create a copy of the currently selected object in this phase, choose 'Objects' from the main menu followed by 'Duplicate the selected object'.
You will then be presented with the appropriate window (as above) giving you the opportunity to change any information or settings for the new object.
After clicking 'Ok' on that window the new, duplicate object will be 'attached' the the mouse pointer just as when adding an object. Move the mouse pointer to where you want the duplicate object to be positioned and click the mouse button to place the object.
You can also copy a selected object to another phase. Choose 'Objects' from the main menu followed by 'Copy the selected object to another phase'.
You will then be presented with a list of the other phases from which you select the one to copy to. A duplicate of the selected object will be placed on the other phase in the same position and orientation as the original.
Once an object has been selected, it can be removed simply by pressing the 'delete' key on the keyboard.
Alternatively, you can select 'Objects' from the menu, followed by 'remove the selected object'.

If you change your mind you can choose 'undo' (see 'changing your mind').