I want to loop keyframes in Blenders Curve Editor. But I can't find a way to do this.

If I select the curve / keys I want to loop and right click and select the animated channel and select "extrapolation method" - they are greyed out and I can't change anything.

It seems like it tries to tell me to use "F-Modifiers" - but I can't find them in the interface ("shift-E" doesn't work as I am using industry standard keys).

A short search in the Blender documentation only reveals screenshots of an older interface version and I can't find the "F-Mod" / "Modifiers" Buttons in the 2.8(1) Version. (https://docs.blender.org/manual/en/latest/editors/graph_editor/fcurves/modifiers.html)

Do you know where I have to click or a tutorial that explains it?