As per our project requirement- I have made form in odoo V12.It includes header section and line items section.So I want to add 5 rows by default in line items in tree view mode and below 5 rows , add more rows button shall be there as well.How can I achieve it?

<notebook>
                        <page string="Slit Details">
                     <field name="slit_details" style="width:25%;align:right">
                                 <tree string="Slit Details" editable="bottom">
                                   <field name="width" style="align:right"/>
                                   <field name="quantity" style="align:right"/>
                                   
                       
                        </tree>
                        </field>

                               
                        </page>
                        </notebook>