Hi Mohit,
1.The tree hierarchy of the objects can be set from the project options.
Project Properties > Open Applications >Web Testing ( select tree model as Tree )
The way to use the tree object effectively is to get the reference of the parent object of the required object and get child object using Find method. The depth to which child object is to be identified can be specified in Find method.
2.If the id,name are not available or not consistent, you can use the classname or objectType for object recognition. Also the combination of multiple properties can be used to find the objects.
Regards,
Amit