OpenWrt installation on Fritzbox 4040

Installing and Using OpenWrt
1

Hello I try to install openwrt with this tutorial which image do I have to download and how do I get that as a bootloader ???

https://fritz-tools.readthedocs.io/de/latest/

Error message is always No potential image file found!

2

See the FB4040 devicepage for images + instructions.
https://openwrt.org/toh/avm/avm_fritz_box_4040

3

how do I get that as a suitable image?

4

See section: "OpenWrt firmware install."