How to arm spoilers

Hello, sorry about this one, but what is the key kombination or a key to arm
spoilers. I wish to complete t.o config in ecam (airbus)

You can assign whatever keystroke available trough Fs control assignments or Fsuipc. In Fs check under "Control surfaces". Fsuipc must be registered if you choose that way.

Flightsim Default is SHIFT + /

Best regards,

Trev