Change/make new keybinds in ne TS Beta

How do i make/change keybinds in the new BETA?
cant figure out.

In the settings under Key Bindings you have the possibility to change them as you like.

Ye, but how to make new ones?
I wanna make keybinds to change channel etc.

Thats not possible

But why isnt this possible?`
TS 3 has that feature. It is really important to me. TS5 is usesless without it, for me.