To begin, there are six people in the friend group. The six people are Ross, Monica, Chandler, Joey, Rachael, and Phoebe. Ross and Monica are siblings and Monica and Rachael are friends from high school and now they are roommates. Chandler and Joey are roommates and they live across the hall from Monica and Rachael. Ross and Chandler are friends from college. Finally, Phoebe and Ross don't live in the same apartment building as the rest of them, they both live separately in different apartments buildings.
It was a normal day, Monica, Rachael, Chandler, Ross, Joey, and Phoebe were getting their morning coffee at Central Perk and complaining about having to go to work that day. Gunther, as usual, was listening in to their conversation and added that he wished he didn't have to be at work right now. Ross was listening intently every time Rachael would talk. At this point, everyone but Rachael knows that Ross has a huge crush on Rachael. So, everything that Ross does that shows he likes Rachael is completely obvious to every but Rachael. The rest of the group has to make sure they don't let this secret out to Rachael because it's Ross's responsibility to tell Rachael this.
Then, everyone went to work. Later in the day, Ross was talking with Monica and Phoebe about how much he liked Rachael. Then, Monica added in embarrassing stories about Ross trying to impress Rachael when they were in high school, which is when Ross first started to like Rachael. The rest of the group met up with Ross, Monica, and Phoebe for dinner in Monica and Rachael's apartment for dinner. They were all having casual conversation when the topic of prom came up. As a result of this, Monica brings out her and Rachael's senior prom video from when they were getting ready and Monica's house and getting ready to leave for prom. In the video, it shows that Rachael's date Chip doesn't show up. Rachael is devastated because this means that she doesn't get to go to her senior prom. Because Ross liked Rachael at the time and he also wanted to make sure that Rachael was happy, he decided that he would surprise Rachael and take her to prom instead so that she could still have a good time, even though her date didn't show up. Meanwhile, Ross goes upstairs to get ready and when he comes downstairs he finds out that Chip had arrived and they were all leaving to go to prom. No one but Ross and Monica's parents knew that Ross was going to do this for Rachael, until now. After seeing the video, Monica comments to Ross about how nice it was for him to be willing to take to her high school prom, even though he was in college at the time. Then, Rachael runs over to Ross and gives he a kiss because he was so kind and generous for willing to do this for her, just so she could go to her senior prom. This is one of the first incidents, that shows Rachael that Ross has feeling for her.