Find and calculate time between two events

I'm trying to figure out the best way to process data using Excel. To start I want to say I'm new to Excel for heavy duty things like this but I'm a fast learner and starting to dive into VBA.

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So I have a list of events with their timestamps. I'm trying to basically add up times between two events (every event has an on and an off). The events are not together as there is a lot of other data. Timestamps are in column A in M/D/Y H:M format with 24 hour time. The event name is in column B. The number of the device is in column C.

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So just to try to clarify I would like to find the time difference between Event_A_On and Event_A_Off for a specific device and then add up these times over an 8 hour period (not just any 8 hours but do it for 3 separate 8 hour periods as we're trying to process data per shift if possible).

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As I said, I'm new to this so please let me know if anything I'm asking is dumb or not possible