All Sonoff modules run Sonoff-Tasmota.
These switches are used to control other Sonoff modules.
Go to /co and set the Friendly Name 1 to something descriptive (e.g. Attic switch 1), save (will restart and reset any other config).
Go to /md and set Module type to Generic (18), save (will restart). Go back to /md and set D2 GPIO4 to Button2 (18) and D1 GPIO5 to Button3 (19), save again. Make sure not to use Button1 (17) as that button can accidentally be used to reset the config. (You can also use the following template: {"NAME":"Benni Switch","GPIO":[255,255,255,255,18,19,255,255,255,255,255,255,255],"FLAG":1,"BASE":18}.)
Go to /cs and configure the following rule:
Rule1 on button3#state do publish cmnd/light-large-attic/power toggle endon on button2#state do publish cmnd/light-small-attic/power toggle endon
Enable it with Rule1 on.