I'd like to create a kind of dynamic subform which could shown up based on a dropdown list and would be populated by data from other forms. With other words it would be a pre-filled subform by 4-8 rows in that. See below the sub-form. Only the quantity would be optionally editable by the user, other field should be pre-filled based on a previous choice from the main form.

I was able to add data from a form but only into the first row of the subform. Is it possible to add to more rows?

If it is not possible, is there other solutions to manage this? i.e. getting a pop up window like when edit record? 

Thank you