For instance, consider that we would like to associate a customized Contacts view to the Account form.
Let's see how quickly it could be done with this nice feature.
Navigate to Settings->Solutions->Entity->Account Entity->Account Form->Insert
You could see a Sub-Grid option. First place your cursor on the form where you want to insert the Sub-Grid. Its always a good practice to add it in a new section. And then click the Sub-Grid button.
We prefer to show only related contacts records of the Account entity. There is an option to edit the existing view or we could define a new view. Click on Edit button.
You could add or remove columns as per your preference. Once this is done click save and close.
Note: Sometimes you may need to Publish the contact entity separately in order to see the modified view on the Account form. Its because this view is of another entity and there is no publish option on this navigation.
As shown above, the Sub-Grid displays the Contacts on the Account form. This provides a quick view of the related contacts of the corresponding Account to the End-User. As mentioned before this grid could be customized according to the requirements.