Electric showers, I dunno if I'm being dumb but mine doesn't work and I don't know if that's a me fault or not?

Do any of you have an electric shower and if so how do you work them?

I've pressed and held the on button I've checked the boiler and there's no shower switches, the water looks as though it's on with the drew stop flow switch thing (don't know the proper word for it). There's a random switch in the hallway which I have no idea what's it for but didn't seem to do anything with the shower and can't think of anything else that could be the problem.
Electric showers, I dunno if I'm being dumb but mine doesn't work and I don't know if that's a me fault or not?
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