Scroll down to the download link and tap the primary (europe) link.
Tap download link with the latest version means the first one on the list.
Next again tap download link to get custom recovery to POCO X3 NFC on your computer.
Root process on the POCO device will erase all of your data.
All described operations you are doing at your own risk.
If want to save your data do a backup before start.
The battery should be at least 50% charged before the start.