Selecting the whole row at a time

I'm unsure what you mean by "whole row" - when you use selection in an Editable Grid the result of selection is to save the value of the provided identifier into whatever target variable you want, and then you can do anything you want with that (such as pressing a button / clicking a link to remove the row from your form by removing that row of data from your CDT array, or if it's already in the database, slate its primary key ID for row-deletion using a subsequent Delete from DSE node).  The official Appian Documentation has quite a bit of guidance on this.

I'm unsure what you mean by "whole row" - when you use selection in an Editable Grid the result of selection is to save the value of the provided identifier into whatever target variable you want, and then you can do anything you want with that (such as pressing a button / clicking a link to remove the row from your form by removing that row of data from your CDT array, or if it's already in the database, slate its primary key ID for row-deletion using a subsequent Delete from DSE node).  The official Appian Documentation has quite a bit of guidance on this.

That is correct. On and editable grid you can also choose the selection style to be 'ROW_HIGHLIGHT' if you prefer that over the checkbox from a UI perspective.