Multiple AND /OR conditions in caml query

Just continue to nest the queries...

if (!string.IsNullOrEmpty(txtFullName.Text) || !string.IsNullOrEmpty(txtEmail.Text) || !string.IsNullOrEmpty(txtHandPhone.Text) || !string.IsNullOrEmpty(txtExtension.Text) || ddlDivision.SelectedItem.Value != "0" || ddlBranch.SelectedItem.Value != "0")

                {
              SPQuery query = new SPQuery();

                    query.Query =

                 "<OrderBy>" +

                 " <FieldRef Name='ID' />" +

                 "</OrderBy>" +

                 "<Where>" +

                  "<Or>" +

                   " <Contains><FieldRef Name='FullName' /><Value Type='Text'>" + txtFullName.Text + "</Value></Contains>" +

                        "<Or>" +

                        " <Contains><FieldRef Name='DID' /><Value Type='Text'>" + txtExtension.Text + "</Value></Contains>" +

                        "<Or>" +

                            " <Contains><FieldRef Name='Handphone' /><Value Type='Text'>" + txtHandPhone.Text + "</Value></Contains>" +                         

                            "<Or>" +

                              " <Contains><FieldRef Name='Branch' /><Value Type='Text'>" + ddlBranch.SelectedItem.Text + "</Value></Contains>" +

                                "<Or>" +

                                " <Contains><FieldRef Name='Division' /><Value Type='Text'>" + ddlDivision.SelectedItem.Text + "</Value></Contains>" +                    

                                 " <Contains><FieldRef Name='Email' /><Value Type='Text'>" + txtEmail.Text + "</Value></Contains>" +

                                "</Or>" +

                             "</Or>" +

                        "</Or>" +

                    "</Or>" +

                 "</Or>" +

                 "</Where>";

                }

-----------------AND Condition-------------

<And>
    <Eq>... condition...</Eq>
    <And>
        <Eq>... condition...</Eq>
        <And>
            <Eq>... condition...</Eq>
            <And>
                <Eq>... condition...</Eq>
                <Eq>... condition...</Eq>
            </And>
        </And>
    </And>
</And>