VS 2005 With Datagrid Events

i am developing a small asp.net application in vs 2005. my application consists of 3 layers.presentation, business layer and data layer. now i got a small problem in using datagrid events like itemcommand , databound events in presentation layer. this is my first asp.net application with different layers , upto now i dint work with layers. i created datagrid as follows <asp:datagrid id="datagrid1" runat="server" /> in my page load i craeted an instance for my businesslayer as mywebsite businesslayer .customerinfo cs = new mywebsite businesslayer .customerinfo(); in customer info i have a function to bind the grid

bindgrid(datagrid dg1, datatable dt)
{
dg1.datasource=dt;
dg1.databind();
}

now i want to add itemcommand event ad databound events. can any one advice me how to add these events and where should i have to add these events?