How to recover old WhatsApp chats on iPhone?

Hello everyone,

does anyone knows that, how to backup the WhatsApp messages?

first time, I backup the WhatsApp data the time the data was 23gb later I lost my mobile and I download the WhatsApp on new device and I started the WhatsApp without restore the old backup…

second time, I uninstalled and reinstalled WhatsApp that time only takes the new backup data of 400MB not showing of 23gb data…

I want to get all the data… how I can get this?

can anyone help me out?

thanks

[Re-Titled by Moderator]