Weird... you aren't missing a step. I haven't been able to work on the game, because honestly I got discouraged a lot by one of the addons I was using. I'll probably be redoing the hands entirely.
To press the switch, you need to pull or click the "grab" button. It's also very awkwardly placed in the current build, you kind of have to aim as if you're trying to hold it. I'm sorry about this! I'll try to work up the courage to get back into development and design.