d-akui, i dont quite get what you mean, most distortion pedals work by stepping on it, hence the name "stomp box" as for small buttons, the keeley and randolf ones only have a switch between regular and ultra mode, that one is hard to change while playing(unless you got three hands), but as for activating and deactivating the effect, just stomp on it man.
if the "small switch" youre referring to is the MXR sort, then not to worry, its perfectly easy. nothing too hard that you need a degree to figure out.