Since I haven't read it, it's hard to say for sure. But if it's named 'Howard Get the Door', Howard is likely one of the main characters. There could be other characters such as people who come to the door, like a delivery person, an old acquaintance, or a mysterious stranger.
We can only speculate, but Howard is the central character as per the title. There could be a mentor - like figure who has sent someone to Howard's door for a test or a task. Or perhaps there's a pet in the story that has some sort of reaction every time Howard gets the door, which could make the pet an important secondary character.
Chapter 809, "Specially Made for You", is the clearest early answer because it turns Jiang Bufan's situation into a concrete plot event. The chapter gives readers a real answer by opening on Listening to the cries from inside the house that sounded like a pig...
Chapter 858, "If You Dare, Take It", is the clearest early answer because it turns Jiang Buchen's situation into a concrete plot event.
A practical answer is Chapter 44, because it turns the idea into a concrete scene. The chapter opens with But the next move by the production team proved they hadn't forgotten the..., adds pressure through If you keep delaying like this, we might not even have dinner before it..., and ends on Does.
Look to Chapter 34 for the clearest answer. It begins with Seeing that the public sentiment wasn't quite right, Su Yinwan felt..., keeps building through It was she who had anonymously paid someone to write the critical article..., and lands on Now that Lili is misunderstood, they start to kick us.
Chapter 846, "Locked up for 6 months!", is the clearest early answer because it turns Mom's situation into a concrete plot event. The chapter turns that into something concrete by moving from She took a deep breath, and a guilty expression immediately appeared...
The best chapter pointer here is Chapter 34, "Official Recording!". It opens with Seeing that the public sentiment wasn't quite right, Su Yinwan felt... and closes on Now that Lili is misunderstood, they start to kick us while we're down."....
Chapter 843, "Why the Sudden Change of Heart?!", is the clearest early answer because it turns Uncle Zhao's situation into a concrete plot event.
Look to Chapter 27 for the clearest answer. It begins with They had spent an entire year gradually inviting a few people., keeps building through The pressure they endured during this period was beyond words., and lands on Yes, I'm sorry." He nervously twisted his hands, "I was impulsive.".
A practical answer is Chapter 18, because it turns the idea into a concrete scene. The chapter opens with In the corner, a girl in a black dress sat quietly, holding a glass of..., adds pressure through I have no reason to joke with the rest of my life." "Moreover, I wouldn't..., and ends on Hurry.
Chapter 20 is the strongest chapter-level answer because it starts from Several people turned their heads upon hearing the sound and saw three... and follows through on So, he turned and questioned Jiang Li..