Angular-TS designing model classes

I have a page with a drop-down box and two input box elements. This drop-down has 8 values to select from. The two inputs are associated with each one of the the drop-down values, except one of the drop-down value display a popup window which has a table with 10 rows & 4 columns (fixed), each row has a check box and 3 input boxes (2 of them are same as the parent page plus one extra).

User should be able to select one or more check box(es) and fill-in input boxes. If the user was selected 4 check boxes, I should show the table in the parent page on save.

I have a model class for the drop-down box value (id & string). I have a model class for the 10 check boxes (id & string). How should I design the main model class as one of the value has 1:M relationship? Should I keep a separate array of objects? In that case, how do I attach it with the main model class? Thanks.

Source: Angular Questions