# Extent Mapping page

Here is shown data related with one entity data type pair (ARM and AIM).Data can be merged from several models (in the case that you are working on schema instance instead of model). At the top are list of models in the combobox, ARM entity data type name and AIM entity data type name. Current modelin combo box will change automatically to instance model when you select instance. In the list below are all instances which fits with both ARM and AIM entity data types mapping and are in these models. If you want to create instance of thistype you need to select model in which you will create it and press 'Create'button. If you want to delete instance you need to select one and press 'Delete'button. 'Get' button is for further editing operations. If you select instanceand press 'Get' than selected instance will be placed in sdai clipboard andyou will be able to use set operation later. More for editing see instance mapping.