In a more complex plot diagram, you will often see these categories going up and down the stairs to the climax in order:
Exposition/Beginning, Rising Action, Climax/Middle, Falling Action, and then the Resolution/End.
This helps to remember because the rising action (building of the conflict) would be categorized and placed before the climax. The climax should also be known as when the conflict is finally brought to the surface. A character should spend their entire falling action trying to find a way to resolve it. Because of this, your answer is going to be 'in the beginning.' This is when you are going to see the conflict start to build as it struggles to reach the middle or the climax. Remember that the climax is most likely where you are going to hit the breaking point and major importance of the conflict. You are rising (action) and building up towards it.
When I got back my mom had cooked dinner.
Nicked was dancing at a party when he met his gf.
What did you do last weekend?
I finished that series on netflix. I did not like the ending.
Linda was surfing when the shark attacked her.
I was talking to my friend on the phone when the bus arrived.
When the earthquake happened, they were sleeping.
What did she do at 9:00 last night?
What did she see while she was swimming?
I think these are right but I could be wrong
I believe it is to add sensory words to appeal to the reader and make it more interesting. I hope this helps!