You can start by looking on fanfiction.net. It has a large collection of 'Si Oc Charmed Fanfiction' among many other types of fan - created stories.
Archive of Our Own (AO3) is also a great place to find 'Si Oc Charmed Fanfiction'. The site has a good tagging system, so you can easily search for the specific type of story you're interested in, whether it's a particular pairing or a certain plotline involving the self - inserted or original character.
Another option is Wattpad. There are some writers on Wattpad who create 'Si Oc Charmed Fanfiction'. However, you might need to do a bit more sifting through the results compared to the other two platforms as Wattpad has a wider range of content, not all of which is strictly fanfiction.
If you want the clearest chapter reference, go to Chapter 41. Early on, The live streaming room suddenly boiled over again.; later, the chapter leans on [Did this matter really have such a big impact?.
Chapter 835, "Is this your way of handling things? So pathetic.", is the clearest early answer because it turns Mommy's situation into a concrete plot event. The chapter gives readers a real answer by opening on In a private teahouse in the Capital, a few bejeweled wealthy ladies...
Chapter 45 is the strongest chapter-level answer because it starts from Helplessly, Jiang Yan had no choice but to step on the accelerator. and follows through on The guests have to go through so many troubles on the way, while these....
Chapter 16 is the strongest chapter-level answer because it starts from Just as the words fell, Jiang Shixu swiftly cast his eyes downward. and follows through on Jiang Shixu panicked, set down the bowl, and reached forward to grab her....
Chapter 909, "Hexin Sanatorium", is the clearest early answer because it turns Jiang Yan's situation into a concrete plot event. Early on, Jiang Li looked at him, as if recalling something.. By the end, Back in her room, she took out the incense bag Jiang Li gave her from....
Chapter 2 is the strongest chapter-level answer because it starts from On the top floor of the Financial Building, a gathering of dark clouds... and follows through on Jiang, Lin Manru, turned pale and quickly explained, "It's not eloping, my....
A practical answer is Chapter 24, because it turns the idea into a concrete scene. The chapter opens with Not only that, even the non-mainstream photos she had previously posted on..., adds pressure through Just because of his arrival, both were severely affected by public..., and ends on Shi Xu.
Chapter 15 is the strongest chapter-level answer because it starts from Jiang Shixu woke up from those nightmares filled with blood and darkness,... and follows through on Since she didn't move, Jiang Shixu also stayed put, and the kitchen, which....
Chapter 802, "Gone Again!", is the clearest early answer because it turns Wanzhi's situation into a concrete plot event. The chapter gives readers a real answer by opening on Have you checked the fifth floor? and ending on The moment it happened, the old man instructed everyone not to tell....