by learning on this Forum.
https://doc.e.foundation/devices/FP4/install
https://doc.e.foundation/devices/FP2/install
e-2.1-r-20240606407290-dev-FP2.zip is the lastest build released less than a week ago.
https://images.ecloud.global/dev/FP2/
you can complain here :
Fairphone - FP2 - FP2 - Documentation Suggestions