Add Rows to a DataTable without losing the previous rows

Question

I am developing an application in windows forms

I have two grids (grid1 and grid2)

I have a textbox and two buttons (search and group).

By clicking on the search button I do a search according to the entry in the textbox,

and the result is assigned to a DataTable to then display it in the first grid.
My question is how do I make each search result is displayed in the second grid without losing the data?
ie to accumulate in the second grid