odoo/addons/account_followup/followup_demo.xml

<?xml version="1.0" encoding="utf-8"?>
<terp>
    <data noupdate="1">
        
        <record id="demo_followup1" model="account_followup.followup">
            <field name="name">Default follow-up</field>
            <field name="description">First letter after 15 net days, 30 net days and 45 days end of month levels.</field>
        </record>
        
        <record id="demo_followup_line1" model="account_followup.followup.line">
            <field name="name">Level 0 : 15 net days</field>
            <field name="sequence">0</field>
            <field name="start">days</field>
            <field name="delay">15</field>
            <field name="followup_id" ref="demo_followup1"/>
        </record>
        <record id="demo_followup_line2" model="account_followup.followup.line">
            <field name="name">Level 1 : 30 net days</field>
            <field name="sequence">1</field>
            <field name="start">days</field>
            <field name="delay">30</field>
            <field name="followup_id" ref="demo_followup1"/>
        </record>
        <record id="demo_followup_line3" model="account_followup.followup.line">
            <field name="name">Level 2 : 45 days end of month</field>
            <field name="sequence">2</field>
            <field name="start">end_of_month</field>
            <field name="delay">45</field>
            <field name="followup_id" ref="demo_followup1"/>
        </record>
        
    </data>
</terp>