Dang - use the handles structure that is passed in as the third parameter to the push button callback to get the handles to the three edit text controls. If the table is part of your GUI (i.e. an uitable) then you would again use the handles structure to get the table handle and use that to update the table. For example,
function pushbutton1_Callback(hObject, eventdata, handles)
% get the string data from the three edit controls
str1 = char(get(handles.edit1,'String'));
str2 = char(get(handles.edit2,'String'));
str3 = char(get(handles.edit3,'String'));
% do some work
% update the table
set(handles.uitable1,'Data',data);
where data is an mxn cell array of data that you wish to display within your table.
