You can start by looking on fanfiction - net. It has a vast collection of Hunger Games - related fanfictions and there's a good chance you'll find some that focus on Prim watching the games there.
Archive of Our Own (AO3) is another great place. It has a very organized tagging system. Just search for 'Prim' and 'The Hunger Games' and you'll be presented with various fanfictions that might be what you're looking for.
A practical answer is Chapter 133, because it turns the idea into a concrete scene. The chapter opens with Watching Jiang Li and the others finish their meal and tidy up the table,..., adds pressure through Yet, He Wen could perceive a touch of melancholy in that sharp and..., and ends on It was.
Chapter 209 is the strongest chapter-level answer because it starts from He Yun suddenly spilled out over a dozen cards. and follows through on While he, after a whole bunch of them poured out, ended up with only nine.... The payoff is that the chapter closes with Damn, who is this guy?
If you want the clearest chapter reference, go to Chapter 159. Early on, Seeing the red light of the camera turn on, Su Yinwan looked at the...; later, the chapter leans on Sorry, director, it was my staff who didn't arrange things well, that's....
A practical answer is Chapter 207, because it turns the idea into a concrete scene. The chapter opens with After finishing, Sister-in-law Lan quickly took out the Good Evaluation..., adds pressure through I didn't say I'd pay you for your work, did I?, and ends on She had taken care of them for a.
The best chapter pointer here is Chapter 156, "Group Morning Run!". It opens with Flash Change, who was always tardy, was late again today. and closes on Soon after, the meditative He Yun also walked over..
If you want the clearest chapter reference, go to Chapter 160. Early on, As the sky gradually darkened, the originally mild drizzle began to...; later, the chapter leans on Jiang Li looked up at the sky and turned to the people behind him and....
A practical answer is Chapter 190, because it turns the idea into a concrete scene. The chapter opens with Several people who didn't understand fell silent., adds pressure through And it became even more repugnant to him., and ends on Because he saw the pack of cigarettes pinched between Jiang.
The best chapter pointer here is Chapter 148, "None are Normal". It opens with Exiting the cottage, Director Sun picked up the phone. and closes on Just as Jiang Li put down her chopsticks, she received the call from Mr..
A practical answer is Chapter 188, because it turns the idea into a concrete scene. The chapter opens with With a "snap," the pencil Jiang Cheng was using to draw broke on the paper., adds pressure through Not to mention their utterly chaotic fertilizer spreading actions later., and ends on I.
If you want the clearest chapter reference, go to Chapter 183. Early on, Seeing that he held a blue ball identical to Su Yinwan's, Jiang Yan...; later, the chapter leans on Yinwan, it seems we're destined to be partners," he said..